... what?
It seems like your first sentence is asking what qualifies Hairy_Hen to be able to accurately recreate the 70mm Dolby six-track mix. That's simple. He has access to an in-theater recording of the 70mm mix, which he can use to compare what was and what wasn't in that mix.
Since all research that has been done points to the 1993 mix being a fold-down of the Dolby six-track mix with added effects, he used that as a base, then used the 1977 theatrical stereo mix (taken from laserdisc) to replace the parts in the 1993 mix that have added sound effects.
He then had Satanika upmix this track (which was in stereo) to a 5.0 mix. Then, using a combination of the 1997 SE laserdisc 5.1, the 2004 DVD 5.1, and the 1993 stereo mix, he created a brand-new hybrid LFE track for the film that attempts to recreate the LFE of the 70mm mix as faithfully as possible. He then added that to the 5.0 upmix, and voila - a 5.1 Dolby Digital recreation of the 1977 Dolby six-track mix!
Obviously, this isn't perfect, for a few reasons:
1) The 5.1 mix has a center, front right, front left, surround right, and surround left channel, as well as one LFE channel. However, the 1977 six-track mix had three front channels (R, C, L, same as the 5.1 mix), but only one rear surround channel (compared to the two rear surround channels of the 5.1 mix). Also, the 1977 six-track mix had two LFE channels. In other words, it was a 4.2 mix, not a 5.1 mix.
2) Because he was working from an in-theater audio recording made by a fan, there's no way of knowing where certain sound effects would have been placed, or exactly how much LFE would have been present at which time.
3) The 1977 stereo mix, which was used to fill the gaps in the 1993 mix where new sound effects were added, has less dynamic range than the 1993 mix does. Therefore, someone with sharp ears will be able to tell the difference between the two sources. Plus, it's likely that the 1977 stereo mix differs slightly from the 1977 70mm six-track mix, so those parts, while more "original" than the 1993 mix, may not be exactly what they should be for the Dolby six-track mix.
So, while it's not THE Dolby six-track mix, it's damn close, and a very impressive listening experience in its own right, especially for the custom-made LFE track, which kicks the 2004 5.1 mix's ass. Hard.
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Now, your second sentence seems like you're asking Hairy_hen to send you three free DVD copies of the movie with the 5.1 mix. The post you quoted has the download links for the 5.1 mix itself, which (I would assume) is all that Hairy_hen is going to give out.
Dark_Jedi, however, will soon be releasing version 3 of his custom-made theatrical cut DVDs, which will include hairy_hen's 5.1 mixes.
So you have three options:
1) Download the 5.1 AC3 file and make a DVD of your own using the video 2006 DVD (1977 theatrical disc, obvioulsy)
2) PM someone who already has made a copy and see if they'll be nice enough to send one your way
3) Wait for Dark_Jedi to finish with his V3 DVD set, and get it from him, or from someone who will be getting it from him.
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Sorry if I misread your post - if I have, disregard mine.