First: LED lights for sure as they have no ballast and are not temp or humidity sensitive. Size the intake air filters so there is a good air flow but not a tornado. Absolutely seal everything so ALL air flow goes through filters. Have lights from floor to ceiling to prevent shadows. We have two booths, a home made and pricey DeVilbis in it's own building. The home made gives cleaner paint jobs because the painter is a cleanly nut and the one in the high dollar booth is a pig. No booth can compensate for carried in trash and sloppy wash and wipe downs. Our home made booth has an open from the bottom door (like ones on concession stands) that gives a tight seal when lowered down into place. A 19' long booth will work with most older cars/trucks but a 4dr long bed truck has to go in the DeVilbis.

Evan