99% of the valves in player piano action stacks are regulated to the
same travel.  If the valve travels too little, the note plays slowly.
An airtight system only loses pressure while the valve is in motion
and if travel is too wide the system loses too much suction.  A piano
with a wider than optimal valve travel will fade out in volume if an
arpeggiated run is played or if there are many repeating notes.

For optimal playing I find that the minimum valve travel is .032", but
I set all mine to .035" to .040" maximum.  One exception is Simplex
which can play well on as little as .028" valve travel.  A reproducing
piano needs more precision and gets set to precisely .035".

Digital depth gauge micrometers are quite cheap at Harbor Freight if
you need one.

Hope this helps and best of luck in regulating.

Doug L. Bullock