The Welte-Mignon Licensee system requires that all tracker bar holes
be the same size.  In the Duo-Art player, the eight dynamic holes
are well above the normally sized holes below, so this would not be
a problem.  However, with the sustaining and soft pedal holes, the
situation is different.

To satisfy the purist, there would have to be an entirely separate row
of holes beneath the Duo-Art row, with a complex shifter valve similar
to that used on the 65/88-note combination players.  Or, perhaps there
could be a vertical row of three holes for each of the pedal functions,
with only the center hole engaged when playing a Welte roll.

Jeffrey R. Wood