If the "two mics-multi-track thing" is true that would be an easy way to see if a gig was multi-tracked, but obviously there were no double mics at MSG 1973, EC 1975, or Knebworth, so what's the deal with using two mics?
I believe he only had access to the angles used on the big screens. It looks like there were more angles used because he mixed footage from two nights and also mixed footage of different songs. (I think there are some snippets from Moby Dick during Stairway.)