Dash: Your quote “And regarding the Mamzer issue there is a Chazakah that a Mamzer whose status is unknown will not pollute the gene pool so there is a limit on how far back research is required.” was a Chiddush that I had that I thought was against the Rama. R’ Schachter said it’s not a Kasha on the Rama. These people’s status are all known-they’re Safek Mamzerim.
nisht: It’s in Yabia Omer, Chelek 6 or 7, I think.