as a painter do not buy car type paints but use commercial two pack poly as i would use for spraying .£150 will get you top coat and if you do not want to do to much rubbing down just key the surface and use two pack etch which smells like cat piss and put on very light.
com two pack poly can be sprayed on at almost full strength without thining using a 2 /2.5 flued nozel on a cravity gun such as a binks 630 and any good painter should be able to layup to about 10 thu wet drying to 5 all in one pass.i would use jutan clark /spencer or sigma,you could use international yacht paint which gives a good finish but it runs easy and would be better doing two coats,any bus or coach sprayer will sort this for you.