I thought back, and I thought I could have done enough wrong with my first test to have my paint turn out as easily scratchable as it was. On my test area, I preped the surface with 150 then dusted with a rag, and I used water to clean the foam roller (not a good idea, and not fun). It could be I had dust left on the surface, and/or got some water mixed in with the paint mixture as I applied it (since I reused a roller that had some water hiding in it).

so I'm trying it again using the same stuff, but this time I'm using only mineral spirits to clean the roller, and I sanded the surface with 80, then 240, then cleaned it with mineral spirits and a rag and let it dry.

So I've just applied the first coat..and I'll scratch test each coat until I'm done.

I wonder how the "clear" rustoleum would do, if applied full strength (or thinned?) over a 6 coats of thinned color (+ wetsanding). It might help a bit with gloss or add to scratch resistance.