I'm skeptical; in all the time I've bought 5.25 inch floppy diskettes
(since 1976), I've NEVER seen one that had a shorter head window. I'd
be willing to pay $20 for such a diskette for my collection.
I have em. Both 10 sector NS* format (no even for $20 I dont give them
up) and also some of my TI99/4a likely others that I'd have bought around
78-79. Drive me nuts when I went to the 40 track SA400L. Kept getting
errors beyond track 36! Turns out the media has a smaller window.
I've seen plenty of DRIVES that couldn't step
past tracks 34-36, but
that was a mechanical limitation of the drive.
I know, I still have the SA400 supplied with my MDS-A, a 35 track model
and a lot of media from back then for the ICOM FDOS controller.
Allison