I had a full size 45 glock grip countour changed.....my local gunsmith did this before it became common, I contacted glock and told them what we were going to do and the guy responded that if we ruined the frame he would sell us another one.........My local gunsmith wasnt worried i was,lol.....he filled in the hollow of the back strap with fiberglass and cut out that swell on the back strap, and we experimented a little with it, we added finger grooves and mess like that, we wound up removing the grooves and contouring the backstrap straight. Joe colored the fiberglass black and mixed some epoxy with color and added fine sand to it.....covered the entire grip and it provided a very secure grip......grip was still a little big for me, but the work and idea was right. The uniqueness here is how easy it is to add fingergrips and then remove them if they arent what you want--although it will fill in the "checkering",,,,also when the sand on the grip wears off, it is easy to replace and works well...fubsy.