5000 grit? That seems awful high. I usually use 400 grit to just scuff it, then use a couple of coats of automotive primer, then spray a few light coats with whatever, then clear it 4 - 6 times, then go back through and wet sand it with 1500 or 2000 grit, then hit it with some Meguiars (or other) nice wax and buff it to a purty shine!
-Jonathan
