Normally you wont have any problems with the 2k paint as this has hardened off completly, so you could use anything. The best stuff is polyurethane 3k or 2k. One thing is very important, be sure to give everything a good rubbing down, and use the right primer for the right paint. If i was you i would buy a cheap compressor and gun on flea bay.
Then spray the bulkhead's etc etc, and things that yer can't get too,its don't matter if there is some dust in the bulkheads,so you can spray them outside on a dry day, assemble everything,
Then have a look around in the yellow pages for spraying booths for hire, the shell has to be 100% so that will need the spraying booth.
As for inside the doors and wheel wells use Dinitrol, just did mine this summer whole kit cost me 100 quid but it is a lot better than that waxoil ****e. Dinitrol is the best on the market for sure.
For your information, the car industry use water based paint, which is useless. you have to look to the aviation industry or some other heavy industry for polyurethanes. Professional use only. Lots of Chromates and other dangerous stuff in there.
Good Luck