I do what Bubby said. That ERC I just posted is the first bow I've done without a cut in shelf, so I kinda had to ponder what to do with that floppy rest. I grabbed it like I had been shooting it, stuck the floppy right on top of my knuckle, and lightly marked it. With the others, I've just shot it a bit so see where it's happiest with the arrow location, marked it, and cut away anywhere from just a bump as a glorified locator to a full blown radiused shelf if there is room.