I think you'd have better luck with transferring files via a CompactFlash card or an SD card.
Look into the
Floppy Emu (on a Quadra, you would plug it in via ribbon cable to your motherboard in the same socket that's currently connecting the motherboard to the floppy drive) or one of several SCSI to CF/SD solutions such as
SCSI2SD or Artmix's
CF AztecMonster.
FWIW, most late 90s USB (specifically, USB 1.1) was slow to the point that you wouldn't want to be using it for very long. Least that was the case when I had a G3 iMac.
CompactFlash and SD cards transfer files at faster speeds. You'll be happier with those.