So what do the trim pots in the MP-1 do?

[tabascojunkie]

Hmm?

[rnolan]

Make you loose weight LOL.  Try a search on trim pots, there's a few posts about MP1 trim pots, MJMP posted to explain the OD1/2 trim pots.
There are a bunch of trim pots in the MP1/2, they adjust various things (voltages within a circuit). So e.g. you can change the gain +/- in the OD 1 and/or OD2 circuits, you can change the chorus (RandallRG's area IIRC), there may be others...

OD1/OD2 trim pots are probably the focus though..