Hi, the UHD version have better compression and more detail than the BD 2D version. The colors are also better.
For make an “ultimate” version, this is the best version to use despite the flaws that UHD has.

I would combine UHD with Blu-Ray 3D scenes which have more visible image.

And I have a 35mm scan project that will allow me to share (for donors) a 35mm grindhouse version, but also to recover 2 scenes that have been modified on BD/UHD/3D and integrate them into my custom UHD project .

The modified UHD version is intended to be shared with everyone, but if people participate in the 35mm project, the modified UHD version will move faster too 😃

I see where you’re coming from and just hoping this all goes well. Also, kinda unrelated but since you have “French original dub” in the title, which implies this got redubbed, what’s the difference between the two French dubs?