I looked at the pictures in your gallery; that booth looks really nice. It's too bad it didn't work out too well. I've had fairly good results with a booth made in the garage. As you noted the main problem is getting enough light. I keep getting more lights but it still isn't enough. I think I'm going to have to go all out and buy a bunch of flourescent light tubes and mount them on the walls and ceiling.
The worst problem with mine is that I leave part of the door open for the exhaust. This works fine until evening and the bugs are attracted to the light. A few days ago I had a beautiful coat of clear ruined by a little fly. DOH! Now I'm going to filter the exhaust too so that nothing can get in.
Anyway, good luck with your next booth.