From my reading on here, many use more clear coat to begin with on a show car. Therfore you can safely level without running into your base coat. Most guys state they start with 800 on a block and work their way up. The 800 on a hard block cuts the peel out fast and the thinner grit prepares it for polishing. I was also reading you want to go finer than 1500 so that you are not taking as much off with the polish. I never did understand how the polish took off more than the sand paper. But you would probably go all they way to 2500-3000 if you wanted it like a mirror.

A daily driver with 2 coats of clear, I buffed mine at 1500 and did not bother going finer. You cannot see the sand scratches unless you really study the paint in direct sunlight.