Just learned, via a consultation today, that I probably don't need to pull the old drywall, especially since I am thinking of doing a second layer, and there is blown in insulation behind the old drywall. This makes the conduit question more complicated. (It also makes re-doing the wiring, which the consultant strongly recommended, more complicated.)
I'm beginning to like the idea of raceways, and outlets on the outside of the drywall surface, and so on -- then covered with light curtains or fabric. I could place acoustic treatment there, as well, and than might work nicely.