Dad’s 1969 Dodge Dart Swinger 340

As for filters I was speaking of how my friend's shop booth was set up.

I didn't mention (you are 100% correct) fan show blow "out", creating slight negative pressure in the booth and filter bank should be on opposite end of makeshift booth.
Plastic sheet the walls and ceiling too. Many ways to skin that cat. Oh, don't spray primer in the booth, easy to sand it versus another coat of plastic sheeting / basically rebuild the booth before color coat.