Regardless of what exactly it contained, one thing is clear: reconstructing the 70mm audio would be a lot of work, much more than was involved in doing Star Wars.

So . . . here's what I'll do. I'm going to proceed as planned with the ESB 5.1 that I mentioned, which will be part of dark_jedi's newest AviSynth encodes; and if a larger attempt is made to recreate a 70mm version of Empire, I will certainly be on board, but it will be its own separate project from what I'm doing now. I'll help with that for whichever approach is taken, whether it keeps the edit the same as the 35 or the picture is altered along with the sound.

Does it strike anyone else as odd that so many lines apparently existed in the first cut of the film but were then taken out for the 35mm version? If you look at Star Wars, all the dialogue differences in the mono version were recorded later, but in the case of Empire, we seem to be expected to believe that a "more complete" auditory experience existed first, and was then cut down for the later wide release. Combine that with differences in the SE not being authentic, and something just isn't adding up at all. Hence my scepticism about the whole thing . . .