Quoted from maffewl:

Update. I've now tried rolling, brushing, wiping... you name it... bubbles. I've thinned it to 30%, 50%, and even further. I do not see how this stuff can ever be used for its intended purpose. Bubbles, bubbles everywhere.
If anyone has had success and/or may have means or methods that I haven't tried, please send them as I have plenty of the stuff left to test. However, I've pretty much given up on using this as a clearcoat for a playfield.