Yes thin the acrylic with bottled water and strain the paint to get any clumps out. That way you get a nice even layer of paint and no clogs in the gun. Best practice is to spray real light coats and wait about 10 minutes between coats to dry so the paint doesn't build up and run.Any spray gun will work, but remember you get what you pay for so guns in the $25-$35 range are good enough for low volume  surfboard builders.