It is a non-starter of an idea for a few reasons:

1.  The Orchestrelle is laid out with the lowest 13 notes as single
bass notes and the treble bass division split at G#/A beneath Middle C.
The vast majority of the rolls are arranged with these facts in mind.

2.  The perforations required to produce decent organ music are
fundamentally different than that for pianos.  Organ perforations are
extended for the full duration of the note required.

The reason cut-down 65-note pianos rolls sound dreadful on Orchestrelles
is that the rolls are not cut with regard to the above two factors.

3.  The 58-note system may not like reading narrower perforation
88-note piano rolls, especially those which are chained.  The system
forces air through the perforations and the 58-note player valve
systems are generally larger and more rugged than 88-note player
pianos.  You would need to adjust bleeds and valves, etc.  Altering a
116-note Orchestrelle (which can cope with chain perforated 12/inch
rolls) would be a tragedy.

4.  The entire spool box assembly would have to be replaced as 58/116
rolls are narrower than 88-note rolls.  Cramming an 88-note roll
through the narrow opening in the wooden front of the instrument will
be fiddly -- it's hard enough with large 58-note rolls as it is!

I suggest cutting down a few random old 65-note piano rolls and trying
them out; if the effect produced is disagreeable then you will know why
not to bother changing the tracker bar.  65-note and 88-note piano
rolls will only ever be piano rolls.  On the Orchestrelle their music
will be of the same odd juddery quality whatever you do.

Orchestrelles are rather rare, good playing ones are rarer.  There were
several thousand titles produced; contact Kevin McElhone for a full
list!  When I bought my Orchestrelle last year it came with no music
but I have hunted the stuff down and gradually have assembled a modest
repertoire for it.  Sadly there's no jazz and no modern rolls for the
instrument.  You just have to accept that Orchestrelles don't play
modern or jazz stuff any more than Polyphons will.

However, I am working on a project for some new repertoire: 20th
century orchestral works, modern popular music and some lively hot
jazz, etc.  I am still in the very early stages planning the roll
arrangements and selecting suitable repertoire.  If anyone has any
suggestions as to what might sound good on the instrument let me know
and I'll give it consideration.  My logic is that its easier to make
new music for the instrument.

As to the difference between models I'll leave that to others to
answer!

Yours, Merry Xmas and a Happy New Year, etc.

Adam Ramet
agr@lineone.net