diff --git a/calyx-py/calyx/fifo_oracle.py b/calyx-py/calyx/fifo_oracle.py
index fd943b4a13..156442a0fc 100644
--- a/calyx-py/calyx/fifo_oracle.py
+++ b/calyx-py/calyx/fifo_oracle.py
@@ -1,8 +1,12 @@
+# For usage, see gen_queue_data_expect.sh
+
+import sys
 import calyx.queues as queues
 from calyx import queue_util
 
 if __name__ == "__main__":
+    max_cmds, len = int(sys.argv[1]), int(sys.argv[2])
     commands, values = queue_util.parse_json()
-    fifo = queues.Fifo([], False)
-    ans = queues.operate_queue(commands, values, fifo)
+    fifo = queues.Fifo(len)
+    ans = queues.operate_queue(commands, values, fifo, max_cmds)
     queue_util.dump_json(commands, values, ans)
diff --git a/calyx-py/calyx/gen_queue_data_expect.sh b/calyx-py/calyx/gen_queue_data_expect.sh
new file mode 100755
index 0000000000..d5d32b2487
--- /dev/null
+++ b/calyx-py/calyx/gen_queue_data_expect.sh
@@ -0,0 +1,17 @@
+#!/usr/bin/bash
+
+# For SDN, we use piezo mode when making the data file and
+# use pifotree_oracle to generate the expected output
+python3 queue_data_gen.py 20000 --no-err 16 > ../test/correctness/queues/sdn.data
+cat ../test/correctness/queues/sdn.data | python3 pifo_tree_oracle.py 20000 16 > ../test/correctness/queues/sdn.expect
+
+# For the others, we drop piezo mode for data gen, and we use the appropriate
+# oracle, which is one of the following:
+# - fifo_oracle.py
+# - pifo_oracle.py
+# - pifo_tree_oracle.py
+
+for queue_kind in fifo pifo pifo_tree; do
+    python3 queue_data_gen.py 20000 --no-err 16 > ../test/correctness/queues/$queue_kind.data
+    cat ../test/correctness/queues/$queue_kind.data | python3 ${queue_kind}_oracle.py 20000 16 > ../test/correctness/queues/$queue_kind.expect
+done
diff --git a/calyx-py/calyx/pifo_oracle.py b/calyx-py/calyx/pifo_oracle.py
index 9786ffc699..1d0156d5ad 100644
--- a/calyx-py/calyx/pifo_oracle.py
+++ b/calyx-py/calyx/pifo_oracle.py
@@ -1,11 +1,15 @@
+# For usage, see gen_queue_data_expect.sh
+
+import sys
 import calyx.queues as queues
 from calyx import queue_util
 
 if __name__ == "__main__":
+    max_cmds, len = int(sys.argv[1]), int(sys.argv[2])
     commands, values = queue_util.parse_json()
 
     # Our PIFO is simple: it just orchestrates two FIFOs. The boundary is 200.
-    pifo = queues.Pifo(queues.Fifo([]), queues.Fifo([]), 200, False)
+    pifo = queues.Pifo(queues.Fifo(len), queues.Fifo(len), 200, len)
 
-    ans = queues.operate_queue(commands, values, pifo)
+    ans = queues.operate_queue(commands, values, pifo, max_cmds)
     queue_util.dump_json(commands, values, ans)
diff --git a/calyx-py/calyx/pifotree_oracle.py b/calyx-py/calyx/pifo_tree_oracle.py
similarity index 60%
rename from calyx-py/calyx/pifotree_oracle.py
rename to calyx-py/calyx/pifo_tree_oracle.py
index 6e97727dae..b05e8393fa 100644
--- a/calyx-py/calyx/pifotree_oracle.py
+++ b/calyx-py/calyx/pifo_tree_oracle.py
@@ -1,15 +1,13 @@
-# Usage:
-# To make a .data file:
-# python calyx-py/calyx/queue_data_gen.py --piezo > calyx-py/test/correctness/sdn.data
-# To then make a .expect file:
-# cat calyx-py/test/correctness/sdn.data |
-# python calyx-py/calyx/pifotree_oracle.py > calyx-py/test/correctness/sdn.expect
+# For usage, see gen_queue_data_expect.sh
 
+import sys
 import calyx.queues as queues
 from calyx import queue_util
 
 
 if __name__ == "__main__":
+
+    max_cmds, len = int(sys.argv[1]), int(sys.argv[2])
     commands, values = queue_util.parse_json()
 
     # Our PIFO is a little complicated: it is a tree of queues.
@@ -23,8 +21,11 @@
     #   - The boundary for this is 200.
 
     pifo = queues.Pifo(
-        queues.Pifo(queues.Fifo([]), queues.Fifo([]), 100), queues.Fifo([]), 200, False
+        queues.Pifo(queues.Fifo(len), queues.Fifo(len), 100, len),
+        queues.Fifo(len),
+        200,
+        len,
     )
 
-    ans = queues.operate_queue(commands, values, pifo)
+    ans = queues.operate_queue(commands, values, pifo, max_cmds)
     queue_util.dump_json(commands, values, ans)
diff --git a/calyx-py/calyx/queue_call.py b/calyx-py/calyx/queue_call.py
index 97a0e3de4d..3b874458bb 100644
--- a/calyx-py/calyx/queue_call.py
+++ b/calyx-py/calyx/queue_call.py
@@ -4,7 +4,7 @@
 import calyx.builder as cb
 
 
-def insert_runner(prog, queue, name, stats_component=None):
+def insert_runner(prog, queue, name, num_cmds, stats_component=None):
     """Inserts the component `name` into the program.
     This will be used to `invoke` the component `queue` and feed it one command.
     This component is designed to be invoked by some other component, and does not
@@ -55,8 +55,8 @@ def insert_runner(prog, queue, name, stats_component=None):
     # - ref register `err`, which is raised if an error occurs.
 
     # Our memories and registers, all of which are passed to us by reference.
-    commands = runner.seq_mem_d1("commands", 2, queue_util.MAX_CMDS, 32, is_ref=True)
-    values = runner.seq_mem_d1("values", 32, queue_util.MAX_CMDS, 32, is_ref=True)
+    commands = runner.seq_mem_d1("commands", 2, num_cmds, 32, is_ref=True)
+    values = runner.seq_mem_d1("values", 32, num_cmds, 32, is_ref=True)
     has_ans = runner.reg(1, "has_ans", is_ref=True)
     ans = runner.reg(32, "component_ans", is_ref=True)
     err = runner.reg(1, "component_err", is_ref=True)
@@ -77,8 +77,8 @@ def insert_runner(prog, queue, name, stats_component=None):
     lower_has_ans = runner.reg_store(has_ans, 0, "lower_has_ans")
     not_err = runner.not_use(err.out)
 
-    # Wiring that raises `err` iff `i = MAX_CMDS`.
-    check_if_out_of_cmds, _ = runner.eq_store_in_reg(i.out, queue_util.MAX_CMDS, err)
+    # Wiring that raises `err` iff `i = num_cmds`.
+    check_if_out_of_cmds, _ = runner.eq_store_in_reg(i.out, num_cmds, err)
 
     runner.control += [
         write_cmd_to_reg,  # `cmd := commands[i]`
@@ -119,7 +119,7 @@ def insert_runner(prog, queue, name, stats_component=None):
     return runner
 
 
-def insert_main(prog, queue, controller=None, stats_component=None):
+def insert_main(prog, queue, num_cmds, controller=None, stats_component=None):
     """Inserts the component `main` into the program.
     It triggers the dataplane and controller components.
     """
@@ -128,16 +128,16 @@ def insert_main(prog, queue, controller=None, stats_component=None):
 
     stats = main.cell("stats_main", stats_component) if stats_component else None
     controller = main.cell("controller", controller) if controller else None
-    dataplane = insert_runner(prog, queue, "dataplane", stats_component)
+    dataplane = insert_runner(prog, queue, "dataplane", num_cmds, stats_component)
     dataplane = main.cell("dataplane", dataplane)
 
     has_ans = main.reg(1)
     dataplane_ans = main.reg(32)
     dataplane_err = main.reg(1)
 
-    commands = main.seq_mem_d1("commands", 2, queue_util.MAX_CMDS, 32, is_external=True)
-    values = main.seq_mem_d1("values", 32, queue_util.MAX_CMDS, 32, is_external=True)
-    ans_mem = main.seq_mem_d1("ans_mem", 32, queue_util.MAX_CMDS, 32, is_external=True)
+    commands = main.seq_mem_d1("commands", 2, num_cmds, 32, is_external=True)
+    values = main.seq_mem_d1("values", 32, num_cmds, 32, is_external=True)
+    ans_mem = main.seq_mem_d1("ans_mem", 32, num_cmds, 32, is_external=True)
 
     ans_neq_0 = main.neq_use(dataplane_ans.out, 0)  # ans != 0
 
diff --git a/calyx-py/calyx/queue_data_gen.py b/calyx-py/calyx/queue_data_gen.py
index ea7d9c37cd..f8b0063a3c 100644
--- a/calyx-py/calyx/queue_data_gen.py
+++ b/calyx-py/calyx/queue_data_gen.py
@@ -1,15 +1,10 @@
-# Usage:
-# To make a .data file:
-# python calyx-py/calyx/queue_data_gen.py --piezo > calyx-py/test/correctness/sdn.data
-# To then make a .expect file:
-# cat calyx-py/test/correctness/sdn.data |
-# python calyx-py/calyx/pifotree_oracle.py > calyx-py/test/correctness/sdn.expect
+# For usage, see gen_queue_data_expect.sh
 
 import random
+
 import json
 import sys
-from typing import Dict, Union
-from calyx import queue_util
+from typing import Dict, Union, Optional
 
 FormatType = Dict[str, Union[bool, str, int]]
 
@@ -19,17 +14,16 @@ def format_gen(width: int) -> FormatType:
     return {"is_signed": False, "numeric_type": "bitnum", "width": width}
 
 
-def piezo_special():
+def no_err_cmds_list(queue_size, num_cmds):
     """A special data-gen helper that creates a commands list while
     ensuring that there are:
     - No overflows.
     - No underflows.
-    - (queue_util.MAX_CMDS/2) pushes.
-    - As many pops as there are pushes.
+    - `num_cmds`/2 pushes and `num_cmds`/2 pops.
     A combination of the above means that no packet is left unpopped.
     """
     running_count = 0  # The current size of the queue.
-    push_goal = int(queue_util.MAX_CMDS / 2)  # How many pushes we want overall.
+    push_goal = int(num_cmds / 2)  # How many pushes we want overall.
     total_push_count = 0
     total_pop_count = 0
     commands = []
@@ -39,7 +33,7 @@ def piezo_special():
             # This would make us underflow,
             # so we'll change the command to `push` instead
             command = "push"
-        if command == "push" and running_count == queue_util.QUEUE_SIZE:
+        if command == "push" and running_count == queue_size:
             # This would make us overflow,
             # so we'll change the command to `pop` instead
             command = "pop"
@@ -58,44 +52,47 @@ def piezo_special():
             commands += (push_goal - total_pop_count) * [0]
             break
 
-    assert len(commands) == queue_util.MAX_CMDS
+    assert len(commands) == num_cmds
     return commands
 
 
-def dump_json(piezo: bool):
+def dump_json(num_cmds, no_err: bool, queue_size: Optional[int] = None):
     """Prints a JSON representation of the data to stdout.
     The data itself is populated randomly, following certain rules:
     - It has three "memories": `commands`, `values`, and `ans_mem`.
-    - The `commands` memory has queue_util.MAX_CMDS items, which are 0, 1, or 2.
+    - The `commands` memory has `num_cmds` items, which are 0, 1, or 2.
       0: pop, 1: peek, 2: push
-      If the `piezo` flag is set, then items are chosen from 0 and 2 using a helper.
-    - The `values` memory has queue_util.MAX_CMDS items:
+      If the `no_err` flag is set, then items are chosen from 0 and 2 using a helper.
+    - The `values` memory has `num_cmds` items:
     random values between 0 and 400.
-    - The `ans_mem` memory has queue_util.MAX_CMDS items, all zeroes.
+    - The `ans_mem` memory has `num_cmds` items, all zeroes.
     - Each memory has a `format` field, which is a format object for a bitvector.
     """
     commands = {
         "commands": {
             "data": (
-                piezo_special()
-                if piezo
-                else [random.randint(0, 2) for _ in range(queue_util.MAX_CMDS)]
+                # The `commands` memory has `num_cmds` items, which are all 0, 1, or 2
+                no_err_cmds_list(queue_size, num_cmds)
+                # If the `no_err` flag is set, then we use the special helper
+                # that ensures no overflow or overflow will occur.
+                if no_err
+                else [random.randint(0, 2) for _ in range(num_cmds)]
             ),
             "format": format_gen(2),
         }
     }
     values = {
         "values": {
-            "data": [random.randint(1, 400) for _ in range(queue_util.MAX_CMDS)],
-            # The `values` memory has queue_util.MAX_CMDS items: random values
-            # between 0 and 400.
+            "data": [random.randint(1, 400) for _ in range(num_cmds)],
+            # The `values` memory has `num_cmds` items, whihc are all
+            # random values between 0 and 400.
             "format": format_gen(32),
         }
     }
     ans_mem = {
         "ans_mem": {
-            "data": [0 for _ in range(queue_util.MAX_CMDS)],
-            # The `ans_mem` memory has queue_util.MAX_CMDS items, all zeroes.
+            "data": [0] * num_cmds,
+            # The `ans_mem` memory has `num_cmds` items, all zeroes.
             "format": format_gen(32),
         }
     }
@@ -105,8 +102,10 @@ def dump_json(piezo: bool):
 
 if __name__ == "__main__":
     # Accept a flag that we pass to dump_json.
-    # This says whether we should have any 1s in the `commands` memory.
-
-    piezo = len(sys.argv) > 1 and sys.argv[1] == "--piezo"
+    # This says whether we should use the special no_err helper.
     random.seed(5)
-    dump_json(piezo)
+    num_cmds = int(sys.argv[1])
+    no_err = len(sys.argv) > 2 and sys.argv[2] == "--no-err"
+    if no_err:
+        queue_size = int(sys.argv[3])
+    dump_json(num_cmds, no_err, queue_size if no_err else None)
diff --git a/calyx-py/calyx/queue_util.py b/calyx-py/calyx/queue_util.py
index d91980fa16..c62f94c480 100644
--- a/calyx-py/calyx/queue_util.py
+++ b/calyx-py/calyx/queue_util.py
@@ -1,18 +1,14 @@
 import json
 import sys
 
-MAX_CMDS = 20000
-QUEUE_SIZE = 16
-
 
 def parse_json():
     """Effectively the opposite of `data_gen`:
-    Given a JSON file formatted for Calyx purposes, parse it into its two lists:
-    - The `commands` memory, which has MAX_CMDS items.
-    - The `values` memory, which has MAX_CMDS items.
+    Given a JSON file formatted for Calyx purposes, parses it into two lists:
+    - The `commands` list.
+    - The `values` list.
     Returns the two lists.
     """
-
     data = json.load(sys.stdin)
     commands = data["commands"]["data"]
     values = data["values"]["data"]
diff --git a/calyx-py/calyx/queues.py b/calyx-py/calyx/queues.py
index 8d4f156bd8..bef747d71b 100644
--- a/calyx-py/calyx/queues.py
+++ b/calyx-py/calyx/queues.py
@@ -1,7 +1,6 @@
 from dataclasses import dataclass
 from typing import List
 from typing import Optional
-from calyx import queue_util
 
 
 class QueueError(Exception):
@@ -20,9 +19,9 @@ class Fifo:
     Otherwise, it allows those commands to fail silently but continues the simulation.
     """
 
-    def __init__(self, data: List[int], error_mode=True, max_len: int = None):
-        self.data = data
-        self.max_len = max_len or queue_util.QUEUE_SIZE
+    def __init__(self, max_len: int, error_mode=True):
+        self.data = []
+        self.max_len = max_len
         self.error_mode = error_mode
 
     def push(self, val: int) -> None:
@@ -96,12 +95,19 @@ class Pifo:
     - We increment `pifo_len` by 1.
     """
 
-    def __init__(self, queue_1, queue_2, boundary, error_mode=True, max_len=None):
+    def __init__(
+        self,
+        queue_1,
+        queue_2,
+        boundary,
+        max_len: int,
+        error_mode=True,
+    ):
         self.data = (queue_1, queue_2)
         self.hot = 0
         self.pifo_len = len(queue_1) + len(queue_2)
         self.boundary = boundary
-        self.max_len = max_len or queue_util.QUEUE_SIZE
+        self.max_len = max_len
         self.error_mode = error_mode
         assert (
             self.pifo_len <= self.max_len
@@ -162,7 +168,7 @@ def __len__(self) -> int:
         return self.pifo_len
 
 
-def operate_queue(commands, values, queue):
+def operate_queue(commands, values, queue, max_cmds):
     """Given the two lists, one of commands and one of values.
     Feed these into our queue, and return the answer memory.
     """
@@ -191,6 +197,6 @@ def operate_queue(commands, values, queue):
             except QueueError:
                 break
 
-    # Pad the answer memory with zeroes until it is of length MAX_CMDS.
-    ans += [0] * (queue_util.MAX_CMDS - len(ans))
+    # Pad the answer memory with zeroes until it is of length `max_cmds`.
+    ans += [0] * (max_cmds - len(ans))
     return ans
diff --git a/calyx-py/test/correctness/queues/fifo.py b/calyx-py/test/correctness/queues/fifo.py
index 6e30eaad55..2689f38416 100644
--- a/calyx-py/test/correctness/queues/fifo.py
+++ b/calyx-py/test/correctness/queues/fifo.py
@@ -1,4 +1,5 @@
 # pylint: disable=import-error
+import sys
 import calyx.builder as cb
 import calyx.queue_call as qc
 
@@ -102,9 +103,10 @@ def insert_fifo(prog, name, queue_len_factor=QUEUE_LEN_FACTOR):
 
 def build():
     """Top-level function to build the program."""
+    num_cmds = int(sys.argv[1])
     prog = cb.Builder()
     fifo = insert_fifo(prog, "fifo")
-    qc.insert_main(prog, fifo)
+    qc.insert_main(prog, fifo, num_cmds)
     return prog.program
 
 
diff --git a/calyx-py/test/correctness/queues/pifo.py b/calyx-py/test/correctness/queues/pifo.py
index 687610f220..d01b357ecb 100644
--- a/calyx-py/test/correctness/queues/pifo.py
+++ b/calyx-py/test/correctness/queues/pifo.py
@@ -1,4 +1,5 @@
 # pylint: disable=import-error
+import sys
 import fifo
 import calyx.builder as cb
 import calyx.queue_call as qc
@@ -7,6 +8,7 @@
 # The max length of the queue will be 2^QUEUE_LEN_FACTOR.
 QUEUE_LEN_FACTOR = 4
 
+
 def insert_flow_inference(comp: cb.ComponentBuilder, cmd, flow, boundary, group):
     """The flow is needed when the command is a push.
     If the value to be pushed is less than or equal to {boundary},
@@ -293,11 +295,12 @@ def insert_pifo(
 
 def build():
     """Top-level function to build the program."""
+    num_cmds = int(sys.argv[1])
     prog = cb.Builder()
     fifo_l = fifo.insert_fifo(prog, "fifo_l", QUEUE_LEN_FACTOR)
     fifo_r = fifo.insert_fifo(prog, "fifo_r", QUEUE_LEN_FACTOR)
     pifo = insert_pifo(prog, "pifo", fifo_l, fifo_r, 200)
-    qc.insert_main(prog, pifo)
+    qc.insert_main(prog, pifo, num_cmds)
     return prog.program
 
 
diff --git a/calyx-py/test/correctness/queues/pifo_tree.py b/calyx-py/test/correctness/queues/pifo_tree.py
index 53267a068a..af5f60039a 100644
--- a/calyx-py/test/correctness/queues/pifo_tree.py
+++ b/calyx-py/test/correctness/queues/pifo_tree.py
@@ -1,4 +1,5 @@
 # pylint: disable=import-error
+import sys
 import fifo
 import pifo
 import calyx.builder as cb
@@ -7,13 +8,14 @@
 
 def build():
     """Top-level function to build the program."""
+    num_cmds = int(sys.argv[1])
     prog = cb.Builder()
     fifo_purple = fifo.insert_fifo(prog, "fifo_purple")
     fifo_tangerine = fifo.insert_fifo(prog, "fifo_tangerine")
     pifo_red = pifo.insert_pifo(prog, "pifo_red", fifo_purple, fifo_tangerine, 100)
     fifo_blue = fifo.insert_fifo(prog, "fifo_blue")
     pifo_root = pifo.insert_pifo(prog, "pifo_root", pifo_red, fifo_blue, 200)
-    qc.insert_main(prog, pifo_root)
+    qc.insert_main(prog, pifo_root, num_cmds)
     return prog.program
 
 
diff --git a/calyx-py/test/correctness/queues/sdn.py b/calyx-py/test/correctness/queues/sdn.py
index 4d73ed8843..03d1e7f408 100644
--- a/calyx-py/test/correctness/queues/sdn.py
+++ b/calyx-py/test/correctness/queues/sdn.py
@@ -100,6 +100,9 @@ def build(static=False):
     """Top-level function to build the program.
     The `static` flag determines whether the program is static or dynamic.
     """
+    static = "--static" in sys.argv
+    num_cmds = int(sys.argv[1])
+
     prog = cb.Builder()
     stats_component = insert_stats(prog, "stats", static)
     controller = insert_controller(prog, "controller", stats_component)
@@ -119,11 +122,10 @@ def build(static=False):
     )
     # The root PIFO will take a stats component by reference.
 
-    queue_call.insert_main(prog, pifo_root, controller, stats_component)
+    queue_call.insert_main(prog, pifo_root, num_cmds, controller, stats_component)
     return prog.program
 
 
 # We will have a command line argument to determine whether the program is static.
 if __name__ == "__main__":
-    static = sys.argv[1] == "--static" if len(sys.argv) > 1 else False
-    build(static=static).emit()
+    build().emit()
diff --git a/runt.toml b/runt.toml
index d4c3227ad1..043b705fab 100644
--- a/runt.toml
+++ b/runt.toml
@@ -134,7 +134,7 @@ paths = ["calyx-py/test/correctness/queues/*.py"]
 cmd = """
 name=$(basename {} .py) &&
 dir=$(dirname {}) &&
-python3 {} |\
+python3 {} 20000 |\
  fud e --from calyx --to jq \
        --through verilog \
        --through dat \
@@ -149,7 +149,7 @@ paths = ["calyx-py/test/correctness/queues/sdn.py"]
 cmd = """
 name=$(basename {} .py) &&
 dir=$(dirname {}) &&
-python3 {} |\
+python3 {} 20000 |\
  fud e --from calyx --to jq \
        --through verilog \
        --through dat \
@@ -169,7 +169,7 @@ paths = ["calyx-py/test/correctness/queues/sdn.py"]
 cmd = """
 name=$(basename {} .py) &&
 dir=$(dirname {}) &&
-python3 {} --static |\
+python3 {} 20000 --static |\
  fud e --from calyx --to jq \
        --through verilog \
        --through dat \
@@ -185,7 +185,7 @@ paths = ["calyx-py/test/correctness/queues/sdn.py"]
 cmd = """
 name=$(basename {} .py) &&
 dir=$(dirname {}) &&
-python3 {} --static |\
+python3 {} 20000 --static |\
  fud e --from calyx --to jq \
        --through verilog \
        --through dat \
@@ -588,7 +588,7 @@ fud2 {} --from calyx --to verilog-noverify 2> /dev/null
 name = "fud2 cocotb AXI-wrapped xecution"
 paths = ["yxi/tests/axi/*/*-mem-vec-add-verilog.v"]
 cmd = """
-fud2 {} --from verilog-noverify --to cocotb-axi --set sim.data=yxi/tests/axi/vectorized-add.data 2> /dev/null 
+fud2 {} --from verilog-noverify --to cocotb-axi --set sim.data=yxi/tests/axi/vectorized-add.data 2> /dev/null
 """
 
 ##### Xilinx Tests ######