Would suggest replacing a pot with a good attenuator, if practical. I had to do a custom DIY because of the values but that's a lot of work. Goldpoint, Marchand, and DACT have a lot more options since back then.
Nowadays, would be more inclined to use a series relay board or a chip (PGA2310) with a rotary encoder or LCD touch screen. There are kits for just about everything.