Steinway Double flanges/touchweight

[A440A]

Greetings, 
     I have been blessed with a pair of Steinway uprights, (Stella and
Eleanor, we named them after the widows that sold them to us), of the # 70213
vintage, and remember some of the things that made them go so well. 
    One of the most critical dimensions I found was the thickness of the butt
leather.  There is a very short moment arm between the butt flange center and
the jack's contact point.  Reducing the thickness  here makes a dramatic
increase in weight, (though you can develope a lot of initial velocity!!).  
   If your centers are in the ball park,  try bringing the jack out with shims
under the leather,until you find a point of failure.  See if there is not a
range of touch-weight that is displayed as the thickness changes. 
  You are right, these old, large Steinways are really great instruments, and
with a good action, will play along with the best.  Their soundboards seem to
be especially durable.  
Regards, 
Ed Foote