I'd wish someone would ask the survivng members about those shows in an interview.
Mike was asked during his Goldmine interview back in '92. Dave also gives his recollections of the Boston show in "The Lost Beach Boy" book.
And??? What did Mike have to say? In my memories, (as well as my photos from that first time, & 16mm films of the next time), there was quite a significant change from the first Carnegie show to their return shows. Going to have to get ahold of recordings of the shows to refresh my recall...