Hi Dale, here's a rule of thumb. If you can pump with one foot my
Tempola roll "Waitin' for the Robert E. Lee", or QRS-176, "Stars and
Stripes Forever", and the player will still play solidly, then you
have a tight player. Remember, it's just as important for the player
to be reasonably tight while the notes are "on", too.
In the case of an old player piano, the tighter, the better. I do
remember reading somewhere that reproducing pianos with suction
regulators (the regulators) work a bit better with just a tiny bit
of stack leakage.