S.K.Goodman asked about the possibility of adding a 25 note set of
"bells" (metal bars) to a Standard action foot-pumped player.

   It doesn't matter which valve units you use to operate the bells.
They all take the same amount, when rebuilt properly. It doesn't matter
if you operate the second chest off the pneumatic or off the primaries,
capacity-wise.

   Look at it this way: adding 25 treble notes increases the load about
25%. If you want to get a feel for what 25% feels like, "T" in another
air motor in the stack supply and regulate it to run at about tempo 80.
Put on the Old version of the Star Spangled Banner or something really
great and full of notes, and pump it through with the second air motor
running.

   Adding a reservoir won't gain you anything except evenness which
will last a chord or so.

   88 note rolls are not actually cut specifically for xylophones, and
there may be passages in some rolls which really exhaust you to keep
up. I would suggest a suction box for the times you use the xylophone,
and definitely an on/off switch overall.  BY the way, the Orchestrion
Builder's Manual will give you many different ways of turning it on and
off, which at this point may not be readily apparent if "T"ing into the
secondary valve pouch lines.

Craig B.