I have used the Krylon on 4 back glasses, one of them a white knuckle (it was a great example of Fireball Classic) and will probably use it again.
Experience with 1-5 West System epoxy tells me its probably a better way to go, just haven't figured out the proper technique.
The UV resistant hardener would be a must.
The Triple Thick is a great product for an unusual application,I like it and think it helps, even on cracked glasses( with proper prep, of course.