What would the opinion be of four of these zip-tied side-to-side and set under a garage door for exhausting purposes? Enough airflow to keep you from DFO'ing with a spray-gun in your hand?
I've shot a few cars in a garage. We would "bag" the garage using plastic sheeting like in a Dexter kill room and ventilate using blowers from HF and a porta cool swamp cooler. You'll have to change the pads on the cooler once you are done though. I use these blowers (not just for painting but for everything, welding, cooling in the summer, working with solvents) http://www.harborfre...ator-97762.html and this duct http://www.harborfre...duct-97763.html . Others like Northern have them as well.
Where we would paint the cars has become a full time fab shop so it's a bit dirty and a fair amount of metal shavings no matter how much we clean. To avoid this when I started working on the Miata again I put an Easy Up outside, tarped the sides, wet the ground a bit and also put down plastic sheeting. I still used the blowers and the cooler to vent. I'll finish the interior like this but probably go to a local Maaco we used for my wife's old car who will do a quicky spray on the body for a few hundred as long as I do the prep. Considering I'd spend $80-100 on material from TCP Global and have to deal with the mess and setup it's worth if for me. The first couple of hobby stocks were cool but it's kind of a hassle now.
This was from a few weeks ago.