You’re probably 100% right Bob. Except for maybe r-1 and the powerstop slotted ones. I’d like to see and measure a set of those.
I actually have an ‘inspec’ set of sand cast rotors on my car that were 85% ok. lol. The seals aren’t near most of the hat, except for about 3 lineal inches where the sand mould was crap that portion was thicker than the rest. Kind of like a bulge. I ground it off with a 4 inch angle grinder until they just cleared. I figure as the piston moves out the seal will get pulled away from the hat making the clearance even greater,