I tried the small axial fans but they suck, sorry for the pun. I ended up ebaying a 450 cfm squirrel cage blower 'yeah baby' ! made a wooden frame to hold a chicken wire screen over a large space between the screen and the blower for max extraction...about 30w x 26h i bought some spray booth filters with 2 stage filtration fiberglass...

sucks as it blows ..reminds me of an old girlfriend so I call it Juliet
I tried the little fans but they get crapped up real quick they dont have the best flow angles and build up residue ...adding to the worsening flow rate...making the now clean booth covered in overspray instead of the screen/filter
the blowers arent cheap, mine was $50, but it will pull over-spray into the filter and out through a 8"x 16ft flex tube [ebay]...I had to make a square to round conversion tube out of a large coffee container...took no time....