Another option no one mentioned is multi coat single stage with progressive amounts of clear added. Unsure if you guys have ever done this or seen it done but it's one of the deepest paint jobs you'll ever see. Will NOT work with metalics.
A friend of mine use to do that with great results. I also new a guy in the 80's that would heat a gallon of Acrylic Enamel on a hot plate (scary ****) with hardener mixed in. It would stay thin enough to spray without thinner. His paint jobs were unbelievable! One night he forgot to shut off the hot plate when done and burn't down his garage !
