Well, pulled the seat, tank, air filters and carbs off of the bike today, and came to the conclusion that theres no way in hell I'm going to get the throttle bodies in the position I want them in without cutting them apart. The inlet ports in the head are just spaced too far apart, and there's not enough clearance between them and a frame member to get the throttle bodies installed in a way that'll actually flow fairly well.
Looks like I'll have to cut them apart after all, extend the fuel rail and throttle butterfly shaft, and possibly the idle actuator too. At this point I may just ignore the stock idle valve in the throttle bodies and instead just run a complete solenoid valve with a restrictor to simplify packaging.
The bike as she sits now... mmm look at that rust... er... patina