Tim, the description you give fits perfectly that of a Welte-Mignon
(Licensee) tracker bar.  The "O" roll uses a 90-hole tracker bar,
including the two large holes used to shift from play to reroll and
back again.  You would indeed be "cutting into a Picasso" by enlarging
two of the holes in your bar for this purpose.

Better to use a standard 88-note bar with the sustaining pedal port
for shifting back to play and the large rewind port added -- easily
done because of the blank space around that position.  However,
enlargement of any hole is not absolutely necessary.

The standard 11.25" roll format allows for 100 binary information
channels spaced at nine-to-the-inch.*  As far as I know, there was
never any standard developed for the ten extra channels available
on the "O" scale.  However, with the reroll/play ports being larger,
use of the four adjacent channels would interfere with these vital
functions.  This leaves only six channels available for other purposes,
or four on a 98-hole tracker bar.

Presently there seems to be a lull in the building up of "O" roll
playing orchestrions.  Now is a good time to develop a universal tracker
scale for future paper-roll-playing orchestrion builders.  In fact,
I have already come up with such a scale that will enable a single
fully-orchestrated instrument to duplicate the sound of a Coinola SO,
Seeburg H, Cremona J and just about every other American-built
orchestrion, with the additional provision of features offered by none
of these.  No longer would one need a whole collection.

The secret involves using computers to adapt existing A, G, H, M, O,
etc., arrangements to the universal scale, with special effects added
where appropriate.  An abundance of opportunity would be available to
creative roll artists.  I'm sure many readers will agree that no other
medium can take the place of a paper roll and its associated mechanics
for their visual effect when playing actual musical instruments.  It is
extremely unfortunate that most large American orchestrions have the
roll hidden away beneath the keyboard behind a wood panel! More on all
this later -- not too much later, I hope...

* Due to the effect of atmospheric moisture on piano roll paper, this
is about the maximum practical number for any spacing on a non-sectional
tracker bar subjected to commercial use.

Jeffrey R. Wood