Let me state upfront that I don't shoot wet plate and never intend to... BUT... It seems that most of the wet plates I've seen have the emulsion peeling away from the edges and I've been pondering how to minimize this problem.
My GUESS is that this problem could be vastly reduced by modifying the edges of the glass as follows. I do realize that glass prep and coating methodology are paramount.
1. Use a small very fine attachment (on a Dremel??) or (rig something on the belt sander??) to add a 2-4mm sanded border on the front of the plate.
2. Use a table-top belt sander with a very fine sandpaper to very slightly bevel all four front edges just barely enough to remove their cutting sharpness.
3. Very lightly sand the front-side corners just barely enough to remove their stabbing sharpness.
(all of the above in that precise order)
I'm GUESSING that the elimination of tiny chips and sharp edges along with the addition of the rough area for the emulsion to grab onto would greatly reduce the problem of wet emulsion breaking free from the edges and corners.
I apologize if this is an old idea.