This might not apply but I had to add toe-in to vintage side-pulls with fresh pads, and added a half-washer to the stack. Possible application here would be behind the front washer of the 456E assembly. I cut the washer in half using a big pair of side cutters. A brass washer would assure nothing else gets nicked up.

Mine was a "temporary" fix while I looked for something better, but has proven up to the task and I'm leaving well enough alone.