Are you aiming to make it look like it did on 35mm in regards to the colour grade? I definitely preferred that look over the blu ray, it’s just so much more … convincing?
Either way, while the change in colour is drastic, I am also super interested to see the other changes you have made to the movie, it sounds like the ideal version.

It sounds like you are planning on making similar treatments to II and III as well, am I understanding that correctly? Or have you already made those edits?