Review on BAYTORY Keyhole Diameter T Track Slotting Cutting Tools by Corey Greene

I use this with a CNC router to cut keyholes for hanging things. Something I found was that the 5/16" and 1/2" bits cut almost equal sized holes as if I had put a caliper on them and there was not a full 1/16" difference . Some softwood I could make out Although you can definitely see the difference between 3/8" and 1/2" keyholes, tell me which should be 1/2" and which should be 5/" 16 inches.