One word of caution - this may be something you know already, but a lot of guys don't (including some painters who used to work for me in a manufacturing facility). If you are going to heat that shop for painting, don't get cheap and turn it off when you're done working - keep the heat at the minimum temp recommended by the manufacturer for the minimum cure time. We had steel tanks shot at too low a temp and it caused us no end of headaches.
Good luck!
