Knock yourself out, reversing the amp in the case wasn't my idea, tons of ppl do it! On that epi forum, MOST of the vj pics I saw are switched..
After a little investigation, I've found you can put jp1 on a switch, but not a pot. Clipping jp1 effectively takes one of the caps out of the circuit, one that affects low-pass. Putting resistance in there won't take the cap out of the circuit so it wouldn't do anything until you hit practically wide open anyway. I'm not gonna bother putting jp1 on a switch cuz I can't see ever wanting that dark original tone over the brighter modded tone.
Congrats, enjoy!