A few weeks ago I decoded adywan's ESB 5.1 into individual AIFF files and checked it against the '93 mix from Belbucus. (The timing of my mixes is the same as the '93.) The synch definitely varies throughout the movie; I'm guessing the frame count of the video isn't 100% identical to the GOUT, though it's close. The beginning and end of the movie were both in the vicinity of 8,000 samples (approximately 4 frames) late compared to the Belbucus track, while in the middle it was sometimes off by only half a frame, and other times around 2 or 3 frames. Since it was always later, an initial delay on my mix would definitely be required--I would say somewhere around 170 milliseconds so that the largest discrepancies would be cancelled out, and the smaller variations in the middle will become late rather than sounding in advance of the video (which would be perceived as unnatural).

It's not a perfect solution, but it may be acceptable depending how sensitive you are to synch issues, and definitely better than using no delay value at all. I may try this myself since I'm rather fond of what my version sounds like, and I was blown away by the picture quality adywan managed to achieve, though truth be told his mix sounds very good also--the only issues I have with it are some choices Lucasfilm made when mixing the SE. For optimum results with his 5.1, I would recommend going into your receiver settings and reducing the output volume of the rear speakers by 3 decibels, since the SE's by default seem to have the surround channels at too high a level. (Just don't forget to set them back to normal afterwards!)

Actually, what I've been considering would be to combine adywan's theatrical ESB video with my music-edited mix, since the picture is SE-based and not 100% authentic, while using the 'purist' version for dark_jedi's v3 GOUT, since it is from a transfer of the actual original movie. I would then do the same with RotJ . . . which reminds me that I really need to obtain Harmy's theatrical version of that as well. ;)