How did Harold Powell modify his PEDA Steinway?

Through a trade, I acquired a piano formally owned by Harold Powell
of Klavier Music Rolls.  Powell had modified the piano to suit his
needs.  Now, I am attempting to undo any modifications that Powell
made.  My goal is to have this piano operating as it was originally
intended.  The purpose of this post is to seek any information that
MMDers might have regarding the modifications that were made.

The background of the piano is interesting.  It is a rather rare
model B Steinway with a pedal/electric Duo-Art system.  That means
the piano is 7'6" in length and is a true 7' (or a 6'11") Steinway.
The piano was built in Hamburg, Germany, and Aeolian Ltd. of London
fitted the player mechanism in the instrument, which was then sold
in London from the New Bond Street location.

Harold Powell bought and imported the instrument, apparently from the
late Gerald Stonehill, to be used in his roll business.  I don't know
the date.  Here are a few modifications that I am certain he made:

1.  A new pedal lyre without the pumping mechanism was made, and the
original lyre was retained.  This means the lyres can be switched.

2.  An electric Bodine roll drive was installed near the spool box.
Original roll motor and governor retained.

3.  A crash valve was mounted on the expression box.

Other apparent modifications are (I'm guessing):

4. The 17-inch pump was removed and replaced with 15-inch.

5. Various manual levers (slide valves) on the expression box were
modified.

6. Primary stack valves were installed.

Many years ago when visiting with Harold Powell, I believe he told me
that this piano was used in making audio recordings of Duo-Art rolls
that were issued on his Everest record label.  He may have told me of
other planned uses, but I don't remember, as I was more interested in
the Ampico perforators.

The installation of the primary valves almost looks original.  Denis
Hall of London seemed to think so as well when examined the piano last
month.

This piano will soon be playing again.  The original air motor has been
rebuilt and is ready to install.  As any pedaler will attest, an air
motor is the only way to have proper control.  Major work replacing the
Steinway tubular action rails is complete and the new Renner hammers
are ready for regulation.  The Bodine motor now powers my organ roll
reader.

If any list readers have specific information on this piano, please
let me know.  I do have Julian Dyer's paper, "Understanding the
Pedal-Electric Duo-Art", which is quite good.

Bob Taylor
Missouri