As "hack" as it will sound, I have done some decent work with the cheap Harbor Freight gravity feed paint guns. They are often under $20 and usually come with a 1.3 mm tip. I have to thin out primer to shoot through such a small tip but paint and clear spray fine. You mention needing a pro to paint the car: I have never used a traditional booth. The first 7 cars that I painted were in a residential 2 car garage. I put plastic up to minimize contamination, both on the ceiling and around a perimeter.
Something to consider. Good luck with the project.
