A Floppy Tape drive can co-exist with existing PC floppy drives, whether single or dual. The Tape drive just needs to be connected before the “twist” in the cable:
Image from “The floppy user guide”, section 8:
As you could guess, this means no more than one Tape drive per floppy drive controller. However, notice I said “per controller”: you can install additional controllers and have another Tape drive for each one.
These can be dedicated “high speed” tape controllers like the Colorado FC-10/FC-15/FC-20 or Ditto Dash, or a standard PC Floppy controller card that can be configured as a secondary controller (so as to not clash with the primary).
