Old mouthpieces = bigger bores than modern mouthpieces? I'm not sure about his. If you compare the Dukoff D chamber to an old bari mpc you will find that bore is maybe bigger on the Dukoff? The bore of old saxes are in general smaller compared to modern ones. In the mid 30's most manufactors re-designed thier saxophones to meet the "new" type of music. The mouthpieces were also re-designed. Wider tip openings, shaped bores, baffels .... . Old large mouthpieces on old small bore saxes? small bore mouthpieces on bigger sax bores? To the 30's nearly all mouthpieces had a round chamber with no baffle. Bigger or smaller? I really don't know!
Two soprano mouthpieces. The mouthpiece to the left is an old Selmer (no baffle) and the one to the right is a Dukoff D chamber (high baffle) from the 80's. The chamber is bigger on the Dukoff.
Wider tip openings can be played more "loudly" and they are "brighter" as well. Takes more control to play.
Narrower tip openings needs a little less control and are more "darker/mellow".
Large bores mpc have more "spread" and have a "broad and open" sound. Ensembles.
Small bore mouthpieces gives a more "compact/focused" sound. Solist.
High baffle gives a "brighter and more focus" sound.
Low baffle gives a "darker/mellow and less focused" sound.
There is a Kohlert baritone mouthpiece (from the 30's) for sale here in Sweden.