I have some of the Round 2 kits and the decals are much better then the ones in the older MPC kits.
Which of the Nason automotive clear are you using?
Most of the Nason clear seem to be urethane, but they do have a spray can of Acrylic clear. I'm sure it's either urethane or lacquer based.
I'm looking for a good clear coat that will go over automotive lacquer as well as decals.