diff --git a/src/Renderer/Simulator/NumberHelpers.fs b/src/Renderer/Simulator/NumberHelpers.fs
index 849d38203..4a86eb689 100644
--- a/src/Renderer/Simulator/NumberHelpers.fs
+++ b/src/Renderer/Simulator/NumberHelpers.fs
@@ -328,21 +328,14 @@ let UInt32ToPaddedString maxChars radix (width: int) (fd: uint32) =
         let pre, digits = stripLeadingZeros s
         let n = digits.Length
 
-        let pre' =
-            (match displayRadix with
-             | Dec
-             | SDec -> ""
-             | _ -> $"{width}'")
-            + pre
-
-        if pre'.Length + digits.Length <= maxChars then
+        if pre.Length + digits.Length <= maxChars then
             // stripping leading zeros makes length ok
-            pre' + digits
+            pre + digits
         else
             // truncate MS digits replacing by '..'
-            pre'
+            pre
             + ".."
-            + digits[n + 2 + pre'.Length - maxChars .. n - 1]
+            + digits[n + 2 + pre.Length - maxChars .. n - 1]
 let BigIntToPaddedString maxChars radix (width: int) (fd: bigint) =
     let getPrefixAndDigits (s: string) =
         match s.Length, s.[0], s.[1] with
@@ -376,21 +369,16 @@ let BigIntToPaddedString maxChars radix (width: int) (fd: bigint) =
         let pre, digits = stripLeadingZeros s
         let n = digits.Length
 
-        let pre' =
-            (match displayRadix with
-             | Dec
-             | SDec -> ""
-             | _ -> $"{width}'")
-            + pre
+    
 
-        if pre'.Length + digits.Length <= maxChars then
+        if pre.Length + digits.Length <= maxChars then
             // stripping leading zeros makes length ok
-            pre' + digits
+            pre + digits
         else
             // truncate MS digits replacing by '..'
-            pre'
+            pre
             + ".."
-            + digits[n + 2 + pre'.Length - maxChars .. n - 1]
+            + digits[n + 2 + pre.Length - maxChars .. n - 1]
 
 /// Convert an int into a Bit list with the provided width. The Least
 /// Significant Bits are the one with low index (e.g. LSB is at position 0, MSB
diff --git a/src/Renderer/UI/ModelHelpers.fs b/src/Renderer/UI/ModelHelpers.fs
index 5a0c106be..f65320bb6 100644
--- a/src/Renderer/UI/ModelHelpers.fs
+++ b/src/Renderer/UI/ModelHelpers.fs
@@ -15,8 +15,9 @@ module Constants =
             FirstClock = 0; // first clock accessible - limits scroll range. NOT IMPLEMENTED
             FontSize = 14; // size of text on waveforms
             FontWeight = 500 // weight of text on waveforms
-            } 
-    let maxSimulationSize = 1000000
+            }
+    let maxWarnSimulationSize = 100000
+    let maxSimulationSize = 10000000
     let minScrollingWindow = 200
     let wsButtonHeight = 30
     let wsButtonWidth = 120
diff --git a/src/Renderer/UI/UIPopups.fs b/src/Renderer/UI/UIPopups.fs
index 65d10abe1..89640511e 100644
--- a/src/Renderer/UI/UIPopups.fs
+++ b/src/Renderer/UI/UIPopups.fs
@@ -510,6 +510,9 @@ let dialogWaveSimConfigPopup (dispatch: Msg -> unit) (model:Model) =
                                                                                              be at least {Constants.minScrollingWindow} cycles."
             ["fontsize"], not <| inBounds 12 24 c.FontSize, $"Font size must be between 12 and 24"
             ["fontweight"], not <| inBounds 100 900 c.FontWeight, $"Font weight must be between 100 and 900"
+            [], c.LastClock > Constants.maxWarnSimulationSize, $"Warning: very large simulation lengths and big designs result in high memory use, \
+                                                                 and possible crashes."
+                                                                
         ]  
         |> List.filter (fun (_, isError, _) -> isError)
         |> List.map (fun (key, _, message) -> key, message)
@@ -523,8 +526,11 @@ let dialogWaveSimConfigPopup (dispatch: Msg -> unit) (model:Model) =
     let isValid = List.isEmpty errorKeys
 
     let closeAction changeConfig dispatch model =
+        let wsm = getWSModel model
         if changeConfig then
-            dispatch <| UpdateModel (Optic.set (waveSimModel_ >-> wSConfig_) (Option.defaultValue initWSModel.WSConfig (getWSModel model).WSConfigDialog))
+            let dialog = wsm.WSConfigDialog
+            if dialog = None then printf $"Unexpected WSConfigDialog = None when closing configuration popup. changeConfig = {changeConfig}"
+            dispatch <| UpdateModel (Optic.set (waveSimModel_ >-> wSConfig_) (Option.defaultValue wsm.WSConfig dialog))
         dispatch <| ClosePopup
         dispatch <| UpdateModel (Optic.map (waveSimModel_ >-> wSConfigDialog_) (fun _ -> None))
 
diff --git a/src/Renderer/UI/WaveSim/WaveSimStyle.fs b/src/Renderer/UI/WaveSim/WaveSimStyle.fs
index 1ffed0305..754bfea1d 100644
--- a/src/Renderer/UI/WaveSim/WaveSimStyle.fs
+++ b/src/Renderer/UI/WaveSim/WaveSimStyle.fs
@@ -169,15 +169,19 @@ let endCycle wsModel = wsModel.StartCycle + (wsModel.ShownCycles) - 1
 let zoomOutSVG = DiagramStyle.zoomOutSVG
 let zoomInSVG = DiagramStyle.zoomInSVG
 
-/// Style for top row in wave viewer.
-let topRowStyle = Style [
-    Height Constants.rowHeight
-    BorderBottom "2px solid rgb(219,219,219)"
-]
+let valueTopPadding (ws:WaveSimModel) =
+    (float Constants.rowHeight - float ws.WSConfig.FontSize - 8.) / 2.
+
 
 /// Empty row used in namesColumn and valuesColumn. Shifts these down by one
 /// to allow for the row of clk cycle numbers in waveformsColumn.
-let topRow topRowContent = [ div [ topRowStyle ] topRowContent ]
+let topRow (ws:WaveSimModel) topRowContent =
+    [ div [ Style [
+                Height Constants.rowHeight
+                BorderBottom "2px solid rgb(219,219,219)"
+                PaddingTop (valueTopPadding ws)
+            ]]
+          topRowContent ]
 
 /// Style for showing error messages in waveform simulator.
 let errorMessageStyle = Style [
@@ -471,14 +475,18 @@ let nameLabelStyle isHovered = Style [
         Cursor "grab"
 ]
 
+
+
 /// Style for value label
-let valueLabelStyle = 
+let valueLabelStyle (ws: WaveSimModel)= 
     Style [
         Height Constants.rowHeight
         BorderBottom "1px solid rgb(219,219,219)"
         PaddingLeft Constants.labelPadding
+        PaddingTop (valueTopPadding ws)
         FontFamily Constants.valueColumnFontFamily
-        FontSize Constants.valueColumnFontSize
+        FontSize ws.WSConfig.FontSize
+        FontWeight ws.WSConfig.FontWeight
     ]
 
 /// Prop for Level.left in name row.
@@ -520,7 +528,7 @@ let waveSimColumn = [
     Width "100%"
     Display DisplayOptions.Grid
     GridAutoRows Constants.rowHeight
-    FontSize Constants.valueColumnFontSize
+    //FontSize Constants.valueColumnFontSize
     FontFamily Constants.valueColumnFontFamily
     OverflowX OverflowOptions.Auto
     WhiteSpace WhiteSpaceOptions.Nowrap
@@ -533,6 +541,8 @@ let namesColumnStyle (ws:WaveSimModel) = Style (
         Width (calcNamesColWidth ws)
         Float FloatOptions.Left
         BackgroundColor Constants.namesValuesColumnColor
+        FontSize ws.WSConfig.FontSize
+        FontWeight ws.WSConfig.FontWeight
         BorderRight Constants.borderProperties
         GridColumnStart 1
         OverflowX OverflowOptions.Clip
@@ -572,16 +582,21 @@ let valuesColumnSize wsModel =
     |> (fun (w,num) -> int w + 20, num)
 
 /// Style properties for values column
-let valuesColumnStyle (colWidth:int) = Style (
-    (waveSimColumn) @ [
-        MinWidth colWidth
-        Float FloatOptions.Left
-        BorderLeft Constants.borderProperties
-        OverflowX OverflowOptions.Auto
-        BackgroundColor Constants.namesValuesColumnColor
-        Opacity 1.0
-        GridColumnStart 3
-    ])
+let valuesColumnStyle (ws: WaveSimModel) (colWidth:int) =
+    let size = ws.WSConfig.FontSize
+    let weight = ws.WSConfig.FontWeight
+    Style (
+        (waveSimColumn) @ [
+            FontSize size
+            FontWeight weight
+            MinWidth colWidth
+            Float FloatOptions.Left
+            BorderLeft Constants.borderProperties
+            OverflowX OverflowOptions.Auto
+            BackgroundColor Constants.namesValuesColumnColor
+            Opacity 1.0
+            GridColumnStart 3
+        ])
 
 
 
@@ -596,7 +611,7 @@ let waveRowsStyle width = Style [
     Height "100%" 
     OverflowX OverflowOptions.Hidden
     Display DisplayOptions.Grid
-    FontSize "13px"
+    //FontSize "13px"
     GridAutoRows Constants.rowHeight
     BorderTop Constants.borderProperties
     Width width
diff --git a/src/Renderer/UI/WaveSim/WaveSimWaveforms.fs b/src/Renderer/UI/WaveSim/WaveSimWaveforms.fs
index 2bb1d5729..f4211fa8c 100644
--- a/src/Renderer/UI/WaveSim/WaveSimWaveforms.fs
+++ b/src/Renderer/UI/WaveSim/WaveSimWaveforms.fs
@@ -179,7 +179,7 @@ let namesColumn model wsModel dispatch : ReactElement =
     let rows = 
         nameRows model wsModel dispatch
     div (namesColumnProps wsModel)
-        (List.concat [ topRow []; rows ])
+        (List.concat [ topRow wsModel []; rows ])
     //|> TimeHelpers.instrumentInterval "namesColumn" start
 
 
@@ -199,7 +199,7 @@ let valueRows (wsModel: WaveSimModel) =
         match fd.Width, fd.Dat with
         | 1, Word b -> $" {b}" 
         | _ -> fastDataToPaddedString valueColNumChars wsModel.Radix fd)
-    |> List.map (fun value -> label [ valueLabelStyle ] [ str value ])
+    |> List.map (fun value -> label [ valueLabelStyle wsModel] [ str value ])
     |> (fun rows -> valueColWidth, rows)
 
 
@@ -226,9 +226,13 @@ let private valuesColumn wsModel : ReactElement =
     let start = TimeHelpers.getTimeMs ()
     let width, rows = valueRows wsModel
     let cursorClkNum = wsModel.CurrClkCycleDetail
-    let topRowNumber = [ div [Style [FontSize "10pt" ; VerticalAlign "bottom"; FontWeight "bold"; PaddingLeft "4pt"]] [str (string <| cursorClkNum)] ]
-    div [ HTMLAttr.Id "ValuesCol" ; valuesColumnStyle width]
-        (List.concat [ topRow topRowNumber ; rows ])
+    let topRowNumber = [ div [Style [
+            FontSize wsModel.WSConfig.FontSize ;
+            VerticalAlign "bottom";
+            FontWeight wsModel.WSConfig.FontWeight;
+            PaddingLeft "4pt"]] [str (string <| cursorClkNum)] ]
+    div [ HTMLAttr.Id "ValuesCol" ; valuesColumnStyle wsModel width]
+        (List.concat [ topRow wsModel topRowNumber ; rows ])
     //|> TimeHelpers.instrumentInterval "valuesColumn" start
 
 /// Generate a column of waveforms corresponding to selected waves.