That is a cool little horn!
A guy in the South Shore Brass Band had a York alto thing. Front valves, fixed recording bell, looked just like a mini American baritone.

I subbed with the Chicago Brass Band once (on 'solo' trombone, played awful), one of their alto players had a custom FIVE valve Eb. I don't remember how it was setup but I do remember not understanding it when he explained it to me. eyesrollingback.gif

I also remember one of the Eb tuba guys had a 4 valve Alex Eb. He was able to describe in great detail the different 2nd valve slide positions he had to use.
bloke wrote: Wed Nov 10, 2021 2:09 pm
off-topic:
My slightly-beat-up-but-great-playing YEP-321 (recently "found" in the shop attic, and fixed up "good-enough" to use on a gig) features REMARKABLE #1 slide alignment. It might be worth putting a trigger on it, so that the on-the-fly/in-tune chromatic range is extended down to D.
E-flat: 1
T + 4
D: 2 + 3 + 4
bloke "The bore size (only .571") and small-shank receiver (thus small-shank mouthpieces) really doesn't lend itself to playing nice phat/round 'low C's' anyway."
You should also be able to get Db with the kicker, no? To my recollection 321's have a short 3rd valve slide so C probably ain't happening. Didn't Steve Ferguson offer new versions of the 3rd slide kicker for a while?
Still want to get a fixed bell, front valve King, swap in a leadpipe with a large shank (my cimbasso has a large shank pipe leading to a .562 valve set) and role-play as a German polka baritone player. Bass line or stratospheric finger wiggling, nothing in between.