This one went through a long and torturous build process over almost two years. All I can say is don't believe the "advice" you find on talk_ass. However, in the end, it turned out to be a pretty nice instrument.
The commonest form of pickup combination is parallel wiring. This is absolutely simple - a two-pole switch [OFF-BOTH-OFF] disconnects either of the pickups from the output. The [OFF-BOTH-OFF] switch is actually kind of a rare thing. You won't find one at the hardware store.
Parallel wiring is easily extended to more pickups, although three is usually the limit.