where did you get the single you have now? at a UPS Lost Package Auction?
they lost one of two 77 heads that was shipping in from California a few years ago....
luckily I was able to complete a 3 way trade with two other guys here in Minnesota. we each had a single 77, 093, and 670 head and we each needed a different pair so that was a neat swap and everyone was happy.
Anyway, good luck with the search.