It's interesting that the index hole is not on y-axis, if it is actually used to allow operations. I used all my SS 5.25" as DS just by flipping them I think, and they just worked. You weren't supposed to do that, but all the SS diskettes were coated on the other side, so you just fliped it and it would work, but it wouldn't be certified for that use case.
Just recently I wanted to show my kids the 5.25" floppy disk - I had a small stack somewhere, but could not find it. I have finally found an 3½" floppy and have shown it to my kids (14 y.o. max). Evidently they never used such a thing, but I was genuinely surprised they didn't even know what it was. After a considerable amount of time one of my daughters hesitated but said something like: "Wasn't it like old USB stick thingy?". Given they have no USB stick either that's not bad, I guess. Then I proceeded to explain that a floppy disk is pictured on Save buttons - you just had to see their faces, it was a moment of the big revelation.
It should fit on an DMF MF-2HD (standard double-sided, high density, 90 millimeters microfloppy formatted in Distribution Media Format, holding 1'720'320 bytes).
A storage disk doesn't need ability to do random block writes, if you ditch that you can remove the sector gaps and put more sectors on the drive. The Microsoft DMF format and utility can put 1,720,320 bytes on a drive.