These are cool, but I don't think they're at all necessary. In the grand scheme of things, just another pad to need to seat and that can get out of adjustment.

Technically it helps keep the Eb/Bb in *slightly* better tune, but the meager gain isn't really all that noticeable. Cool to have, though.

Cool improv!

I've heard of them. Far as I know, it was an attempt to even out the intonation on the throat-tone keys. Seems like everybody wants to try to fix those notes, and we inevitably get back to the good old fashioned regular boehm.

Thanks Phil! That's a deep and useful review, from a helpful perspective.

Thanks, Windsong! I'm not sure which parts are useful to you--let me know if you would like more angles.

I took apart and cleaned the top joint (the pads were shot anyway) but all I haven't gotten around to the other one.  It's well-preserved; not a single screw gave me any trouble and the pin hinge thingies all came out with fingertips. I think it could be brought back to life, but would this model even be worth getting repadded?