I sent a PM regarding the two remaining Alexander Mouthpieces.

PM'd

The Conn 1 has a large throat by ordinary standards, 9mm if I remember right, but it's so far down there and the transition is so gradual, that I think it just works out. Honestly I can only just tell the difference, vs. say a Schilke 67 that has a similar rim - not as radical a difference as one ...

I own both (and actually 3 Holton 52's) and they do play different from what I have experienced. The Conn 1 feels like it has an easier articulation but does not feel as robust. A smooth sound for sure. My Holton feels more robust which may or may not have to do with the added mass around the cup ...

My school has one of those. I can see the appeal when they function.