FWIW, this is what my stock '69 re-drilled flanges for 1/2" studs look like. The old 7/16" holes were filled.
You'll get pretty close to the O.D. with press-in studs. These studs are 1/2" X 2" screw ins...........
My Moser re-drilled direct replacement axles have a larger diameter and thicker flange on them with press ins.........