Litmus test...

[tonecut]

TS808 (with a switch between TS808 and TS9) and a Proco Rat...in a 1590BB?
Am I mad for even attempting this? What would be the better size to attempt here?

[Ross]

That's very doable. If you want a bit more room, the 125BB isn't bad.

[Geiri]

It's totally doable because it's basically two circuits and to switch between TS808 and TS9 you need to swap out two resistors so that's two switches right there.