All it is is spacing out washers on the plate from the cutout. I hated it and ran it wide open, then just went straight pipe to save weight and because i never closed it lol.
Basically the plate is a triangle. The top screw should have no washers on it, the left bottom and right bottom are determined by what you want. I think MNIWT said he had 3 on one side and 4 or 5 on another. But eventually just made a tone plate instead