Bob Billings asked, and Robbie echoed, that 6-to-the-inch holes
don't need to be any larger than 9-to-the-inch holes.  While that might
be true for 'newer' 65-note pianos, and also for G-roll-playing
orchestrions, my Aeolian Orchestrelle is very sensitive to different
hole size because of its 'ice-pick' bleeds.

If a hole is too small, or too short, a note is likely not to play.
If the hole is too large, the note will hang on.  I realize that
a pressure system like the Orchestrelle might react differently than
a vacuum system, but I'm sure that the results would be similar.

Bob Loesch
California, USA