I'm not sure if the cropping is *completely* random. I will warn that the 0%-5%-10% boxes in my earlier comparisons may be inaccurate, since some of these screens were cropped or stretched by -1, and may be the wrong aspect ratio or not show the 100% complete frame area. Also, I had to do some guesswork with the binary sunset comparison, since there are no "landmarks" at the top of the screen.
I have your Technidisc rip plus the JSC V8 Project burned, but thanks for the offer.
I'll do the Han chase scene if -1 posts uncropped LPP frames where the whole border is visible. I don't think I can work with the faded frames, they seem to be crooked or bowed, and the gate edges are cropped out.
In the meantime, here's Luke and Ben. Same color coding as before. This time I sourced it from an image with soundtrack and sprocket holes (I cropped off the left sprocket holes). I lined it up with the SMPTE framing chart scan I used to make the 0%-5%-10% diagram, including the blank soundtrack space, so the boxes should line up perfectly:

Again, GOUT is pretty close to 5% cropping, but it's shifted to the right. The JSC is cropped on the sides a little more than the GOUT, and the Technidisc is cropped even more, but both have more on the top and bottom. The JSC basically touches the top of the used frame area (you can even see a bit of the rounded edge in the top right-hand corner), while the Technidisc comes very close to the bottom.
I will point out that both the JSC and Technidisc transfers share a trait of earlier widescreen transfers to crop more on the sides than, so the image would read better on smaller TVs. GOUT is cropped on all sides, but in general it has more on the sides than the other two even if it has less on the top and bottom (and as I demonstrated before, sometimes this is a good thing).
Here are some more 0%-5%-10% comparisons from this part of the film - I'll do the GOUT/JSC/Technidisc comparisons in the future.
Notice, by the way, that some shots occupy the entire usable frame area instead of the standard Panavision aperture. Don't ask me why, I have no idea. For those scenes, I'm guessing that the picture outside of the green border never showed up in any theater.




Here's the 2x stretched SMPTE RP-40 framing chart I use for reference (reduced, the full resolution is much higher), complete with the blank space where the soundtrack is located. (You can see my 0%-5%-10% boxes. I drew in the dark green "target" lines when I was making it, so that I could center the 5% and 10% boxes.)

The full usable picture area is everything to the right of the soundtrack space. The reason I don't think the area to the right of the 0% box ever showed up in theaters is because it falls outside of the SMPTE framing area (the checkerboards), and the projectionist would have lined up the framing so that the image on the screen fell inside the checkerboard.
I'm not sure how many more scenes in the film use the entire frame, since -1 hasn't shared many complete frames including the soundtrack and sprocket holes.
Hey -1, could you do more screenshots like these, just full-frame scans with soundtrack and sprocket holes, and 2x horizontal stretch?