the best copy of 7/10/70 I've encountered was labeled 7/10/70, and it was this tape that established the correct date of the mislabeled "6/24/70a" tape, which we already knew from other consierations wasn't labeled correctly. I think that date is nailed down.
Is there a fresh digital copy around of Weinberg's master hitherto labeled "7/12/70"? It would be useful to be able to consult a copy. The tape labeled "FE 7/12/70" has been around with that label for at least 20 years; DeadBase III has its list in '89. And the other master of "7/11/70", that matches up with Kenny's tape's list, has also been in circulation for 20+ years labeled as such -- it was the source of DeadBase's early lists for the date, although DeadBase's list scrambled the order of tunes. So without hearing a fresh copy of Weinberg's tape with the supposed dating intact (it sure doesn't show up on my cassettes, but I've had them for 15+ years), I'm inclined to see the balance of the evidence pointing the other way. But I'd be delighted to examine new evidence. If we conclude that the list previously called "7/11/70" is in fact the 12th, then what of the 12th? is it the 11th? It can't be the 10th or the 9th, of which we have a few fragments (see the DeadLists entry). Also, the list currently called 7/12 looks more like a last night of run. Does Weinberg's master include the NRPS set?