To get the best effect from an O roll orchestrion you should operate
the pipes from tracker bar holes 13 (on) and 19 (off), and the
glockenspiel from holes 14 (on) and 17 (off).  You may find that the
original manufacturer duplexed the on and off holes so the single extra
instrument operated whenever Instrument 1 or Instrument 2 was requested
by the roll.  If this is the case you will need to retube your existing
lock and cancel.

Also, please remember to add the mechanical mute for the requisite
24 notes on the piano which engages whenever either extra instrument is
playing.  The extra instruments play one octave below the piano notes
punched into the roll from which they play, and by muting the piano
notes when the extra instruments play you get the intended overlap of
the scales and no piano duplication of the extra instrument melody.

Nicholas Simons, GB