You should not pay in full until the vehicle is delivered.
Is it a high end shop? $35k is hard to imagine but also not out of line for concours work.
My only thought is that "rent a paint booth" and not dictating the type of paint being applied seems off. They should be spraying what they know and use with concours results.
California outlawing all petroleum based autopaints? So everything has to be waterbased there now?. You can resell your paint to the other 47 states with no problem - the paint supplier may be able to help you - i'd talk with them.
