Nice to read this here. I never was much interested in this, because I made my own Theatrical cut myself long ago, I think at quite the same time when this started here. Now my interest has become re-newed, because I finally got a German soundtrack without extreme flutter sourced of an optical track of a 35mm copy, which is not of the best quality, but really a gift, because each and every source I inspected had this extreme flutter, best heard short before the end at the final chord of the Requiem (A----men). Simply horrible.
Also English and other soundtracks have some flutter, but not as bad as the German one. I even tried to correct it in small parts with Capstan, but this does work very bad when it comes to vocals - no chance. I always hoped for some A.I. solutions, but up to now there is none for de-flutter that works here, at least I don’t know it.

Ok, so now I got this 4k release, BUT:
The colors are as bad as the most HDR releases of the last years: Brownish, (incorrigible) much too much yellow and a bit too much green, much too less blue. Even when you put in all skills in tone mapping, and even when you watch the 4k itself - The BluRay releases are far better!
There even are scenes that are much too bright, and much too less contrast.

The bit of grain the 4k release has got more than the HD releases is of no use… The HD releases (at least the ones I know) are sharp on the point!
An A. I. 4k-upscale of the HD-source would be of even less use… But this people do not want to understand, so of littlest use is to even discuss this point.

What I want to say: I highly recommend to keep this nice project up! Because the picture is far better than this 4k master, and also the efforts about the sound tracks are a wonderful contribution!
What people say, who know absolutely nothing, is not very important… 😉

By the way: Could you send me the link for the documentary? I would love to see it!