I have updated my project writeup. I have gotten enough data to run a pass of diehard, which mostly looked okay, except for utter failures on some specific tests. I am assuming my whitening algorithm is at fault -- it never pays to invent your own crypto type algorithms -- and I am switching to xorshift64 for another go. Meanwhile I did generate a bit over 1.3 million 64-bit seeds with no duplicates, so it's not a total failure.