I used to use the spray cans of Diamond Clear, and was frustrated at the inconsistent results. I was getting occassional fish eyes and splatter, no matter how careful I was. I even shook the cans attached to a sawzall, and warmed them up first. Never knew if I was going to have to re-do the work until I sprayed.
The answer was buying it in a quart can and shooting with a cheap detail gun- never any issues now.