ryanbabs:
I respect your decision, however,
check
NEC 500.5(B)(1)
FPN No.1 (2)
FPN No.2 (1)(4)(5)
Since this is not "pre-manufactured" Paint Booth, in my humble opinion, I would recommend to install/design everything under Class 1, Div 1.
I'm inclined to this, specially because of FPN No. 2 (4),(5) and also we don't know the amount of "vapors" concentrated in between the ceiling and the roof.
ok, Ryan, that's it, I got to go, hope this helped.