Pouches: To seal or not to seal.  That is the question...

I am at the stage where I am putting the new leather primary pouches on
the Kranich & Bach player action.  The original pouches were extra-thin
tan pneumatic leather and were _not_ sealed.

I am using Columbia Leathers extra-thin tan CPL leather.  I have been
reading through the extensive discussions in the MMD archives relating
to the sealing of leather pouches.  Mostly in the past I have done
Ampico valve block pouches and have used the Al Pebworth method using
Dow Corning 3140 RTV.  It works great.  (Thanks, Al!)

But for ordinary player piano work, is it really necessary to seal these
pouches?

Robert Loeffler makes a good case for not sealing pouches in ordinary
player work[*] and yet there is a general current belief to seal any
and all pouches in ordinary player pianos, band organs, coin pianos,
etc.

Does this really improve the performance on these particular
instruments especially when the original pouches were not sealed?

Bring forth the comments.

Dave Krall

[*] https://www.mmdigest.com/Archives/Digests/200906/2009.06.16.06.html 

 [ Robert Loeffler and other restorers must balance these competing
 [ project goals:
 [
 [ 1. Longevity (life expectancy of the restored system)
 [ 2. Performance
 [ 3. Cost (primarily labor)
 [
 [ The quality of the pouch material and its preparation have a big
 [ impact on all three goals.  Which goal is most important to you?
 [ -- Robbie