Neil, was that 1977 Dolby stereo mix digitally ripped from the LD (or was this mix never in digital form on an LD?). Do you also have the ESB & ROTJ soundtracks from this set, were they theatrical stereo mixes as well?
Again, great idea and wish I could help. Don't have a digital out on my player and only have the US DC set. I could do the commentary as that's on the analog track. I can record up to 24/96, but that's major overkill for this. Btw, I can playback the commentary properly. It was incorrectly flagged as CX and it's not. That's why the volume fluctuates so badly on a lot of players. My player auto-detects an incorrectly turns CX on, but I found the pin inside to pull that disables it. Also, I've checked and the commentary is completely mono, so I could record in stereo and put the movie soundtrack in mono on the other channel. This will make it easier for those wanting to sync it back up to the film.