When I sprayed out my jams I just hit it with a 400 grit, just to scuff it up a bit after I cleaned it. Hit it with one coat. Let it sit for a bit less then an hour (as can says) hit it with another. Waited 48 hours wiped with mineral spirits to clean off dust and hand grease, then hit it once more. The spray takes a while to dry but it's very hard when it does. It seemed to self smooth in all but one place. I'm not sure why but I knocked down the bumps there and hit that jam part with another quick coat. It looks great.

I just painted my bicycle this way (roll and a bit of spray). Pictures later maybe.. It matches my car (the parts thar are finished almost perfect) Really crappy prep job though... It shows :/