This refers to How to use IxxxSender with a bitmap VU meter? - #12 by Matt I misinterpreted the png file there 
I used GIMP. First, took a photo of the VU meter I wanted for a background. Tiled it vertically 63 times in GIMP.
Then I guesstimated the curves by probing X and Y for interesting points. For this I wrote a Tcl script to put the background up as a graphic and report the X/Y position of various mouse clicks. Resetting screen res to like 800x600 helps with this.
Used Excel to guesstimate a formula for the curves ( one for X, one for Y ) . Both curves were second order. Cut, pasted and translated the formulae into a Tcl script to generate expected endpoints of needles as evenly spaced as possible.
I did not translate the coordinates to “center of the bottom” but left them as “upper left hand corner”.
Turns out you can get a script from https://gimp-path-tools.sourceforge.net/ to import things called “Paths” in CSV. Then you merge all the Paths, do what’s called a “Stroke” of the paths and presto.
There’s a lot of detail but brevity and all that.