Hammer Steaming

[Arnold]

I find the discussion about steaming hammers as a voicing technique to be
very interesting and intend to buy one of those steamers to try it, but I
have a few questions.  First, being that steam is being used to induce
moisture into the felt and therefor make it swell, how much does the
result change after the hammers have had a few days or weeks to dry out?
Second, can that set of hammers that really are in need of replacing, but
aren't "down to the wood yet" be revived with this method, or is that
denser layer of felt able to be made softer?  Finally, how about that set
of new hammers that are beginning life already too bright for the
customer?  Finally, I'll bet this method would work to swell key bushings
where the bushing is still in tact, but the piano has either been played
roughly, or,
 "woops" I got a bit too generous with the key easing pliers.  Does
this work, too?