To add to Craig Brougher's comments regarding Duo-Art sustain problems:
all reproducing pianos with hammer rails (as all pianos) must have the
individual dampers set to lift properly.  One service manual suggests
that the hammers be set to move to within "one inch" of the strings" when
the soft pedal is on.  Common practice is to set dampers to lift when the
hammers are 1/2 way to the strings.

Within certain reasonable parameters, there is an element of judgment
involved in choosing the distance to which the hammer rail should move on
any individual piano.  If the soft rail is set to bring the hammers
closer to the strings, the dampers must be set to lift later, or the key
tails will lift them whenever the soft pedal comes on, causing a "muddy"
sound.  This is a common problem with "restored" instruments.

Dampers set to lift too early in the stroke of the hammer also put an
undue burden on the pneumatic and can hinder soft repetition.  If they
are set to lift too late, tones will be improperly sustained during the
stroke of a note.

On either upright or grand pianos, it is vitally important for all
dampers to lift together as though they were made of one piece of
material, at the exact same instant, when the pedal has moved enough to
move any damper.  Failure of dampers to do so is a common and obvious
sign of poor workmanship.

Speaking of special needs of piano actions in reproducing pianos: often
neglected are the stop rails in Ampico grand actions.  Hidden behind the
capstans, these are hardly visible without a flashlight when the action
is assembled; yet they should, in my opinion, always be carefully
adjusted to about 1/32" more key travel than reasonably firm pressure of
the key can compress the front rail punchings.  Without this rail, the
tails of the keys could move beyond the correct amount of after-touch,
thus causing an impure tone.

Other systems and upright Ampicos use limiter rails to stop the throw of
the pneumatics at the appropriate point.  Fastidious adjustment of these
stops will pay off (assuming, of course, the piano action to be restored
and regulated to perfection) in greatly improved tonal beauty.

Larry Broadmoore