I played an Epi Wilshire yesterday at the local GC and really liked it. I had seen pictures, but never played one in person. The Phant-o-matic (Varitone) gave some cool sounds and the thing is super light (if it's really made of mahogany, it must be drilled like swiss cheese). It also had a push button on the horn for a kill switch. I know why I would want a kill switch for times between songs, but having a kill switch cut the sound only as long as you hold the button down seems pretty inconvenient. What am I missing here? I'm sure that there is a good reason for the switch, but I don't see how I could use it.
It's just a cool little effect to have for solos and stuff. Like a manual tremolo effect. I think Dimebag used it occasionally. Buckethead and Tom Morello use it as well. You could easily go to an electronics supply store and buy a DPDT Push On/Off switch and swap out the momentary switch that's in there for what you want to do. Or ignore it altogether.
Youtube search: "Buckethead Jordan" that's how you use it!