Quoted from epeabs:
I spray the clear on and watch it start to "fish eye". Completely dry, it looks like the picture of the green insert below (this was sanded prior with 400 since it is the finest I currently have in house). I just never had this issue while using the Spraymax 2K when doing my BK. I think I'm going to pick up some 2pac tomorrow and a Harbor Fright gravity gun and give it a go. Either that or order another can of Spraymax 2K.
That picture clears things up: the cracks in the insert are what is holding whatever wax/chemical that is causing the fisheye. 2PAC will have the same issue. Since you are putting on a hardtop You need to either:
1) replace that insert and others like it
2) sand the insert until the fisheyed clearcoat is removed, then tape off the insert when you clear the rest of the playfield.
The big thing is you want the insert to look good thru the hardtop, as there is no glue for anything to adhere to on the hardtop. If you were repainting the full playfield without a hardtop then other methods would apply