I seem to recall from my BIOS writing days with CP/M, that the 8" drives had twice the data rate of the 5" drives. They also spun faster, 360 RPM vs 300 RPM. The 8" IBM format was soft sectored 26 sectors of 128 bytes, and the 5" used 16 sectors of 128 bytes or something like that. too many numbers to remember.
At any rate, the four 8" floppies that I still have in my meager collection are all different, for different CPUs, OSes, languages, different sector formats, etc. The closest I came to inter-system compatibility was to write a CP/M floppy reading program for the PDP-11.