In response to Terry Bender, I have arranged a couple of rags for
my 31-note Raffin.  Rags are more difficult than most other music
since they often change key.  It is not too difficult to transpose
music so that it is in a key that fits with the organ's available
notes, but it's more difficult if the original is in two keys.
I would have assumed that there would be more rags available in
31-note than in 20-note because there are more notes in 31 note organ.

I enter the sheet music into Cakewalk (assuming I can't find a clean
MIDI file on the Internet) and then I use Midiboek to transpose to the
best key and range for the organ.  Then it is just a matter of moving
non-playing notes to notes that play, if possible.

Lyle Merithew