For several months I'm been using a program called MIDI File Mapper
for work with MIDI files for mechanical organ music ("band organ,"
"fairground" and "organ grinder" instruments).

Among other things, I have used the program to "convert" Wurlitzer
125 and 150 scale MIDI files from roll scans to MIDI files which will
play well on 20- and 31-note "Raffin" scale instruments.  I can also
put files into or out of the Ames (AMI) scales.

Last week I spread the word about my experiences in a seminar at the
meeting of AMICA (Automated Musical Instrument Collectors of America)
and COAA (Carousel Organ Association of America) in Princeton,
New Jersey.  As a follow-up to my presentation, I posted a description
of the program, and my use of it, at

http://www.wallace-venable.name/mechanical-music/Princeton-Arranging/MIDI%20File%20Mapper%20-%20Preliminary%20Notes.html 

Wallace Venable