I did this (gelcoat) once with a friend of mine. We did the bottom of his H20, but we used the prevail (disposable) sprayers. Once it was sanded, it looked GREAT!!

If you are looking for a paint shop that is large enough, my fathers in KY (on the lake) can handle stuff up to 70' long I think.... He can fit his 55 ton travel lift in there... it's NOT small. They do Imron and every other paint/gelcoat you can think of.