Quoted from mark532011:
I don't see an easy way to put down a layer of clear and sand it smooth when there are dozens of "hills" - if I hammer them in, will they stay? I don't see any easy way to cut the top off without messing up the graphics around them.
Tap those high spots down. Use a red scuff pad and scuff up your playfield before laying down your base layer of 2PAC. Make sure you do not have any shinny spots on your playfield. The 2PAC (automotive clear coat) needs a good surface to adhere to.