Paint Booth

[Toms 57 Chevy]

All I have started building a paint booth inside my shop ( I will post pictures). The question I have and I have heard about positive and negative pressure booths. My booth is 21' long and 12' wide. In my shop I have 2 23"x23" windows that 20" box fans will fit in nicely. I had to build a furdown to to use these. I have built 2 big swing out doors in the back to get the car back in and out. my thought would build some filters in the doors and use 2 fans to pull the draft down and out. I open to all suggestions.
Thanks
Tom