that's what i'm looking into right now as well. i will DEFINITELY clearcoat both my pac-man and the joust 2, but finding the right type of clearcoat won't be an easy choice. as you've said: danger of yellowing. i thought about getting clearcoat in spraycans, but this has to be top notch quality, because i'm afraid the usual cheap stuff from the home depots might yellow over the years. have you looked into this?
regarding the thickness of the top paint layer. i too have those rims of around 0.5 millimeters. phet on the klov forum always uses steel wool to take down the edges and then clearcoats the entire thing afterwards. this way, the whole paint job gets an even finish. however, i'm afraid that using steel wool might ruin the paint job. i might have to try this with some spare stencils!
