Here's another test. I used You_Too's corrected version of another one of -1's hi-res images from the colortiming thread.
First, the GOUT (and it's from the official released GOUT this time):
Now, here's my approximation of how that fits into -1's image:
Again, a bit more on the sides, a little more on the bottom, a little less on the top. And again, the aspect ratio of -1's image, when the proportions are corrected, is wider than the intended ratio.
Right-click on it and view it at full size, and notice the weird garbage on the left side; from the uncropped frames I've seen, the exposure level often "drops off" near the left edge of the frame. In this case, I wonder if the picture may be trailing off "sooner" (i.e., more to the right) than it does in the uncropped frames of other scenes that I've seen.
Here's the same image cropped to 2.39:1:
And here's what it looks like compared to the GOUT framing:
Yes, if the image is re-proportioned, then cropped to 2.35:1-2.40:1, it actually has a teeny tiny bit *less* on the sides than the GOUT.
I think that the cropping for the standard -1 release should be a bit more "open" than that. Here's a suggestion:
The red box is an aspect ratio of 2.35:1, the green areas are if the width were extended out to 2.40:1. This framing fits nicely inside the smaller of the two camera apertures in the film. Here's what this framing looks like on one of the shots with the larger aperture.
Unfortunately, any fixed cropping of the film has to lose that extra picture on the right side. If that picture area were included, the shots with the smaller frame size would have a black bar on the right edge.
I'm not sure, but the Death Star scenes I've been working on may be in the larger aperture, which could explain why they lose more on the sides.
For the main release, I'd probably go with something like the green box I drew, and then adjust the horizontal position so that the opening crawl is centered. (Again, I do think there should be a secondary "uncropped" version which shows as much of the frame as possible, so that we can see all that extra picture, even if it means that some shots have black area on the right.)