In the case of the late Duo-Art with .050" valve travel that plays
perfectly, are you sure?  Where valve travel is most important is
during soft playing, where the valve moves slower.

I recommend using a vacuum gauge and see just how low you can go and
still have [acceptable] note repetition.  My own personal preference
on this type valve is .036".  I'm not surprised about the condition of
the leather as Aeolian used the finest materials available.

Nathan (Skip) Woodhull - S-K Piano
Lima, Ohio