The switch brand doesn't really matter, it just needs to be an On/On DPDT (double pole double throw) mini toggle switch. Mini-toggles typically need a mounting hole about 6mm, which means it should fit nicely in the stock PBG mini pot holes.

Something like either of these:
On/On DPDT mini-toggle, flat handle (I prefer flat handles)
On/On DPDT mini-toggle, bat handle

You just need to make sure the switch collar (with the thread) is long enough to extend through the body so you can get the nut on it.