Weeds,
A amateurs take! While you can do the Rust-Oleum or tractor enamel route, these aren't considered durable conventional automotive paints.
Most automotive paints will be what are referred to as '2K' paints..two part paints. They are catalyzed paints...the paint and a hardener. They harden through chemical reaction quite quickly and can have the bugs and runs sanded out the next day. They are mixed and sprayed on...all done!
The base coat/clear coat process is known as a '2 stage' system. It too is catalyzed, but it has two stages as the name implies. A base color is sprayed on, allowed to dry, then a clear coat is sprayed over that. The base doesn't have to gloss as the clear will add this, plus depth.
Go to a automotive paint store and chat with them. The prices of the paints, hardeners and various sealers and reducers will make your American Express card self destruct.
The beauty of these 2K paints is that they can be wet sanded and polished if your technique was a little lacking. I painted my '51 (in the gallery) in black acrylic enamel many moons ago. This was done one piece at a time in a little garage with a old Bink's #7 syphon gun and a 7 1/2 HP compressor.
If you want to do this, it can be done. If you mind your P's and Q's, you can get a very nice finish...your friends will be amazed.
Hopefully the pros will be along soon to give us the real deal.
Stuart