Keep it simple and use Halfords acrylic rattle cans,(or Holts if you find it cheaper at the local motor factors), we get the same stuff here as the UK.
Solid colours can be polished out, metallics generally dry flat, so need a clearcoat, and then polishing.
Clearing over decals is a topic I won't get into, but it does seal them if that's what you want to do, always do a test as above, but I've never had a problem with the halfords stuff.