OK - since I don't know what you have for a working environment I'll keep this very generic as far as the safety portion of a paint booth..
(1)Your first concern is your own protection and your family's safety. Ask yourself; "how much am I worth?" Am I worth cost of an air supplied paint mask/hood or a charcoal respirator, clean suit, latex gloves, etc. ? It's your call. This is pure common sense.
(1b)How can I keep my family safe from harmful fumes? If you have a detached work space then it's simple, seal it up as best you can.. If you are painting in an attached garage you need to seal every nook and cranny. If you smell paint inside the house you have a problem. If you smell paint outside the house you have a problem. How you chose to do that is up to you.
(1c) Lighting- sealed lighting is a must. if fumes can get to the electrical source you have a bomb in the making. This goes for electrical outlets as well.
(1d) Fire safety - not everyone can afford a commercial sprinkler system or a Halon unit. Keep a good size (up to date) ABC fire extinguisher handy and pray you don't have a fire.
Your second concern is ventilation and VOC recovery. You need filtered airflow going in and going out. The CFM and airspeed will need some tuning to get it right. Baffling the fan units by whatever method is up to you. (cardboard and duct tape will work in a pinch)
VOC recovery is simple; divert the filtered exhaust air into a shallow container of salt water. That will neutralize any nasty airborne chemicals. Some 4 mil plastic sheeting, a little wood framework and some duct tape will get you where you need to go. There are more permanent solutions should you chose to get creative.
If you're looking for a more definitive answers (suggestions) you had better PM me. Google is a wonderful tool as well.
