I haven't had the chance to use them and have been looking into those. If anybody has used them, please tell your experiences. I have spoken to several manufacturers and none of the reps can actually give me any specifics. Like what are they impregnated with specifically, will they have pieces that flake off and cause scratching, how long do they last, etc.
I would like to add that if picture framing still occurs after doing it the way John suggested, perhaps the lippage is so bad that it really ought to be ground down.