Lil Brutto said:

kk650, I'm happy to break it down for you but it depends on what cut you wish to use for your project. US/International, Italian or English Extended? This info will make it easier to advise on what audio/video sources will be required.

I don't think the goal should be to recreate the colours of Mondo; rather the focus, as you said, should be on removing the blanket yellow and optimizing image dynamics so that it looks...good. The regrade settings you used for your screenshots are already a big step in the right direction.

On page 1 of this thread is a description of my project that I posted on the Sergio Leone Web Board in late 2013. I put my project on hold until the release of the 4K BD. If you're intending to recreate the International cut, then this should help clarify things.

Well my initial plan was to regrade whatever cut is on the new 4k remaster which I believe is the US extended cut right? The lack of mono track with original sound effects and the different cuts of this film has complicated matters though.

There have been those on my The Good, the Bad and the Ugly release thread on tehparadox asking for a regraded release for the US theatrical cut as well and mono with the original sound effects for both cuts. I would love to be able to make them happy by including a high quality mono track with original sound effects that fits with the US extended cut with the regrade and then see if I can work out how to recreate the US theatrical cut from the 4k transfer and get a mono track with original sound effects that fits that.

It seems that you and TheHutt are the experts on this film, would either of you be interested in working with me to create a regraded US theatrical cut and US extended cut with mono tracks to make everybody currently angry about the official release having the strong blanket yellow tint and lacking mono with original sound effects happy again?