Buescher True Tone soprano compensator key.

I play a Buescher sop from 1926. The upper register intonation above G has always been problematic: mostly sharp except for C# which was very flat.
While researching what appeared to be an extra tone hole located between D and E on the lower stack I came across a discussion of the "compensator key", a tone hole located above the B key and part of the octave mechanisim. This hole las designed to open a crack on high C# and above, being held closed when any note from high C on down ia played. The amount of opening is controlled by the thickness of the cork under the thumb key which operates the octave mechanisim. Modern techs either don't understand this antiquated mechanisim or just don't want to mess with it and set the cork to leave it closed.
I glued a thin piece of cork on top of what was there under the thumb key and sanded it down until the compensator key opened just a hair. This raised the pitch of high C# and greatly improved the ease of producing the notes above it (the horn is keyed to high F). Back in the day it was referred to as the "bitch key" because of the difficulty of getting the cork to just the right thickness, it took me two tries.
As for the closed pad between low D and E, it is a mechanisim for producing Eb by fingering a D and lifting the middle finger of the right hand. Most techs reverse the spring and keep this pad closed because of leaking problems, which is how I'm leaving mine.

Here's a video of the compensator key in use:
https://www.dropbox.com/s/csxnkkriw1n334p/Buescher%20Sop%20Compensator%20Key.mp4?dl=0

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