Thanks, hairy_hen, that helps a lot. So depending on what you think of the snowspeeder crash sound, the ESB '93 mix could be considered as containing different content. Technically it's different, but not enough to make me care.

BTW, in a way, I do listen to the '93 mixes, via your purist 5.1 mixes. I just had more faith in you to get things right, for example the snowspeeder crash ;)

So our updated list of different-content mixes is:

SW: (1) 77 six-channel, (2) 77 stereo, (3) 77 mono, (4) 85 stereo, (5) 93 stereo

ESB: (1) 80 six-channel, (2) 80 stereo, (3) 80 mono (assuming it's similar to our 16mm mono track?), (4) 8mm mono, (5) 93 stereo (same as 80 stereo except missing snowspeeder crash SFX)

ROTJ: (1) 83/93 stereo/six-channel/mono

...with the caveat that we don't have much info on the ROTJ six-channel or mono tracks and could get surprised by some new mix content at some later date. And the ESB mono story could prove to be much more complicated, if the theatrical mono mix matches neither the 16mm or 8mm in content, which is certainly a possibility.