Hi, I just joined Hackaday because of you!  I really want to build this.  I've gone down the rabbit hole of pots and let me tell you, it goes deep.  My interest is figuring out what pots the manufacutrers are using when they build simulation gear (racing pedals, throttles, joysticks...).  The problem is that these manufacurers do not want you to replace the pots when they fail (and fail they do).  This is a "right to repair" issue for me.  Some have gone so far as to remove the markings or have custom codes printed on the pots so that you have no choice but to go back to them.  If you're using a PC, no problem.  You can replace it with one that is close enough and the calibration software will map out your 0-100%.  However, if you're using a console like a Playstation or Xbox, you're out of luck.  There is no calibration option.  You need to find the exact pot with the exact specs.  This is what got me started down the rabbit hole.  I recently decided on a late career change into Industrial Electronics/Electricity/Automation.  I'm about halfway done my course.  A friend of mine was complaining about his inability to replace/upgrade his pots and I told him "it can't be that hard".  I was wrong!  So now, I need to figure out the ohms, the degree of turn, in/out voltage, torque needed to turn it and whatever else.  I pretty much have to start from the pot and figure out the full spec sheet.  So, looks like I'll be standing on your shoulders.  Thanks for this!  I'll keep you posted in the coming months.

This is very cool. Do you just test the pots until you find the one you need, or are you tweaking other components in the circuit to help trim up the trimpot?

The characterisation isn't really for circuit design, people tend to chuck these into pedals and other circuits without much thought.

I'm trying to build up a bit of a database of different potentiometer characteristics so that modellers have a reference for what they might look like. There is a big field of simulating audio circuits for musicians, live and in studios, and I believe this a (small) step towards making sure that these emulations replicate a circuit's warts and all!