Sounds like in the threads I was reading he did get some tiny bubbles from pushing too hard with the rollover. But sanding then a cut and polish got rid of them.
Have you tried a brush, does it not leave noticeable strokes/lines or do the self levelling properties tend to make that somewhat of a non issue? One other question that wasn't clear from the threads I read, is it advisable to give the playfield a light sand first to help it bond or it doesn't matter?
Have seen results for brush method and its damn good with no lines at all.
Its always best to lightly sand anything you are painting or clearing so the product has a rougher surface to bind to