OK, here's a comparison of a shot with the larger .866 x .732 camera aperture. Same color coding as before (along with dark green for the full .866 x .732 aperture).

Since this comes from one of the very dark, very blue frame scans, I color-corrected it in AviSynth to approximate the original theatrical timing, and did some brightness/contrast adjustment. Unfortunately, this completely blew out the seams in the ceiling lights, but whatever.

If this shot is any indication, the JSC (magenta) and Technidisc (yellow) were sometimes opened up into the area outside the .838 x .700 projection aperture. (This is probably why you can see the glows around the edges in the lightsaber composites.) I'm not yet sure how cropping was handled for scenes with both apertures, like the Mos Eisley stuff. I'll look at those later.

As you can see, the GOUT (cyan) again falls into the .838 x .700 area, off-center up and to the right. The GOUT always seems to be framed above and to the right of frame center. Also notice that none of the transfers show any of the picture outside the .838 x .700 aperture boundary on the right side (light green). Also, all of them are to the right of my hypothetical 5% cropping at .838 x .700 (which I've noticed in my other comparisons).