I suppose every post should start with, You need a OSHA approved booth or you may blow up.
Everything after that would be your taking a chance on doing your self in, that should keep everybody happy.
Now not having the space or money to do this, some of us have to compromise a bit.
You can not have a explosion if the vapors are below or above the explosive limits, ain't gonna happen, ask any fireman about the triangle, oxygen, fuel and heat need to be at certain percentages to have fire.
Least wises in the real world.

If you move enough air, the only place (never say only...I know) your liable to get that would be at the exhaust fan, move enough air and it wouldn't even be there.
The only reason I bought an explosion proof fan is another painter buddy had one of the two 1/2hp basic exhaust fans short out and the paint in the squirrel cage blower caught fire.
He does automotive painting for a living and probably paints more in a year than most of us will in a life time.

I keep hearing ya can never spend to much on safety, well I wished I had the disposable income some must have, but unfortunately I don't, so like a lot of the other people I know, we have to do the best with what we can, or just sit in front of the TV, other than rotting the mind, it's pretty safe there...
imho, this whole thing can be summed up with the word, airflow.
Well...that and a good respirator..
Al.....who's off for his second cup of coffee and will come back and try to figure out what he just posted....