@ConnDirectorFan That's very interesting to hear, that JK are now providing their mouthpieces. So they got out of that business altogether, then.
I never saw their 7EW, but I bought a new 7DW when I visited Praha in 2004 or so. It had a wide rim, which was quite flat, a fairly sharp inner bite and a tiny tiny cup in a heavyweight blank. (Not quite megatone-weight but something like that.) I was coming from a Yamaha 11C4/7C and was hoping for just that little push in endurance/range. The honeymoon was nice. Unfortunately my intonation and tone suffered, and this was when I first discovered my lips are too big to be able to play extremely small sizes. I was young and stupid but a senior section member clued me into that my new mouthpiece was not helping my playing.
(The wide rim promoted some bad habits, too, like I used a lot of pressure those days...)
I passed the MP on to a donation drive, instruments for poor students. Hopefully one of them had thin lips...