That leaves the question of what device to use for cutting. I have a little hand drywall saw, but I'm a bit nervous about the possibility of cutting my wiring with it. And I'm reluctant to buy a Dremel or other brand rotary saw, as it's pretty much a one-trick pony.
Is it possible to use a regular Dremel tool, with or without the flexible shaft extension, and a "saw" bit on it to do a decent job on this kind of project, with less risk of nicking my wiring? Or a Bosch Colt laminate router, perhaps in an oversized template "frame"?
Or should I be doing the drywall cutouts before doing the wiring hookups, then do my insulation and drywall hanging? In which case the hand saw is probably sufficient for the quantity I'm doing on this particular project.