Rear clutch frictions are .063, and other than being thin, are interchangeable with the thicker front clutch plates. Steels are also available in .068 and .080. Snap rings also came in different thicknesses if you have an assortment of those. Cutting the pressure plate like that makes it a PIA to measure clearance and weakens it.. Use an uncut pressure plate or on the outside chance that you have to trim it some, trim the entire width. Use good hi-energy or blue rear clutch plates (12760), along with a mix of thick and thin steels to dial the clearance in. Measure and adjust clearances before oiling everything for assembly. At .012 per disc, that's .060 total clearance. You should be able to get very close to that just adjusting part thicknesses.