TubeNet

King was still providing the 28 mouthpiece when I started playing in the 1960s. As I recall small rim diameter, smaller than 6 1/2AL, more like bach 11 in diameter, but well rounded rim, inside and out, medium deep cup. Well suited for the horn is came with, but most players move onto larger for concert or Bach like 11Cs for lead playing.

This isn't an answer to your original question(s), but I did play a 1910 Conn for a while (I later gave it to my sister), and thought a small-shank Schilke 51D worked pretty well; but I only picked it because I was using a 51D on my other euph (a medium-shank Besson) at the time.

I try to alternate between a 52E2 and 57. I get a much more characteristic sound with the 52E2...but prefer the feel of the 57. I am sure there is another mp solution...but I am done with my "quest for the holy grail (mp). I probably should stick with one or the other and focus my energy on producing a consistent and characteristic sound.

I use a small shank 51D on a lot of things just because my chops and ears like it.

The MPs they came with were very much NOT in the BBB euphonium style.
They were looking for VOLUME (unamplified treble outside, they had pianos for inside), endurance (multi-hour gigs with little rest) and FLEXIBILTY back then, so the "much more trombone" sound is right in the ballpark. Outdoor playing, and agility to match American cornets.

My Mantia double-belled baritone is very small-bored.

Their heritage was the band (often outside) being the only music in town.
The opposite of orchestral brass today, and British Brass Bands.

It does feel very wierd to use the same equipment in the same way today.

bloke wrote:dude...Those responses to your query are friggin' RANDOM !

And this is different than a normal thread HOW!?