Switch set/unset - that just means toggled one way or the other. The switch is just there to work around the problem of losing one of the pickups when you use a mono cable.
A splitter like the one above would work, but I would make up a cable where the split is closer to the amps/pedalboard so there is only one cable to the guitar - or you could use a stereo extension cable going into one of those splitters.