sorry, let me clarify. i took what the op said as if he was referring as SRT.
but you would be correct on your follow up question. RT x RT = RT/SRT
some will be higher grade then others. also just because you purchase a SRT and then get another (from either the same source or a different one). this don't mean all the babies will be faders. it's real hard to tell if you get stable fishes. stable meaning breeding true.
also just a heads up there is a low fertility rate on the srt males.