Wow, I finally had it in my head that I'd compromise on the left/right borders and find the exact number of lines cut from each side. Then I could resize and recenter so that although smaller and with overscan, all subjects in the film would appear the same size as any other NTSC edition (with black borders added to only make up for cropped PAL lines).

Perusing the Official and Unofficial screenshot sites, and playing around with the images I made a discovery. It's completely inconsistent. Completely, oddly, insanely, and randomly inconsistent. In some cases they take 32-40 lines off the left and a few from the right, sometimes none from the left and a few from the right. I even found a scene where the right side has more image (by like 20 lines) than ANY NTSC edition. (Though where they got the extra image area from is beyond me.)

There is too much variablitiy from scene to scene to actually correct for this.
So my final answer is: a movie screen has no overscan region, neither will my DVD. If at a later date this becomes necessary to change, I'll do it, but I'm sure these discs will be obsolete by then. I'm still utilizing a few lines more than the original source PAL laserdisc so resolution loss isn't much of an issue. The only real negative is smaller overall image and that might be an issue for small dimension TVs.

Again, if there are enough people asking, I will release the overscaned version and keep the other for myself only, but as yet, I have heard from no-one actually interested in obtaining a copy who wishes there to be no borders.