What size air compressor to apply raptor liner?

Searched the forum and can't find much on this - I am thinking of doing fiberglass and then coating with raptor liner afterwards for my upcoming build. I don't own an air compressor but plan on getting one so I can use nail guns and other small uses, on the raptor liner website they are saying a 6hp with 150psi capabilities to coat... I cannot see needing a 6hp compressor, but I figured you guys might have better knowledge!
So - all that being said, what size, PSI and hp air compressor did you guys use on your builds? Was it enough?
Thanks!
So - all that being said, what size, PSI and hp air compressor did you guys use on your builds? Was it enough?
Thanks!