For decals you might want to take a look at the microsol and microset system. I've been using it for many years and it makes such a huge difference you won't believe it. Using the Microsol and microset I don't even have to clear gloss coat flat paint before I put the decals down. I usually do anyway just out of habit, but it's not absolutely necessary. With this system, followed by a decent flat clear coat, the decals end up looking like they were painted on, and that's the point, right?