After working with this for some hours, I managed to find some settings that worked well on all three movies!

At first they all came out with a bit of a cyan tint, giving them a look similar to the 70mm scans, but in the end I chose to go for balance instead and added some more red, since the cyan in the 70mm scans is probably because of fading. The only difference between the movies is that I set the saturation higher for SW since it was more desaturated than the other two.

I also added a setting in the script that corrects the aspect ratio. I will change it to a more proper setting later to avoid the loss in resolution that it causes.

Check the screenshots out in the first post, and tell me what you think!