< RX50s are 80 tracks, single sided, double density. They will work only
< reliably with 360K floppies, preferably ones without a hub ring.

No 360k floppies do not!  RX50 is 96tpi and 360k are 48tpi.

< The easiest way to get the 400K images on floppies is to use the PUTR 
< program on a DOS PC with a 1.2MB drive. It can write the images to a 
< 360K disk, switching the 1.2mb drive in the correct setting.
< ftp://ftp.dbit.com/pub/putr/

Putr with a 1.2mb tricked to single sided 250kbS mode is equivilent to
RX50.

I also have teac FD55Fs that will do the 96tpi single sided RX50 format.
I also have a few RX50 drives (spares).

Allison