Ummm , isn't this easy to do with a 3d lut , folks?
I mean, come on. From the previous version it's a slight S curve, and basically some saturation in some of the reds.
A 24x24x24 should be plenty to capture all the nuances of the 'color science' of redgamma 3.
3d Luts are a cinch to make in Nuke.
Maybe I'm misunderstanding peoples needs. Any serious color correction software package supports 3d luts on media import.