Disklavier

Here's a question for the techies.  I have an MX100A but play my 
floppies through a DSR-1. Of course I have to put a disk in the 720 
DD drive on the piano in order for this to all work.  My question is 
when I replace the floppy on my piano MUST it be a 720 double 
density drive?  If so, will any 720 Double Density drive work, (if I 
can find one) or can I replace it with a high density drive since 
I'm playing my disks through the DSR-1.  Thanks.