The small bore Alessi models are now available. You can now have the same rim as on your large shank Griego-Alessi mouthpieces. We feel that we've created a very balanced small bore mouthpiece.
We worked hard to create some specific tools here for your toolbox. The A cup is a great alto mouthpiece. The shallower cup allows this to maintain the desired quality of timbre without backing up on you physically.
For small bore tenor trombones I suggest the A and B cups. The C and D cups are deeper and work well on medium bore instruments (.525"). When the C and D cups are used on a smaller bore (.490"-.508"), some people may have to push in the tuning slide more than they are used to.