A long time ago it was said
"trumpet players with thin lips should choose smaller mouthpieces"
and the reverse about large lipped cats. Read this long long ago I think in my "Bugling Merit Badge" pamphlet from the Boy Scouts. And that book was from well before my time even.
Here's an idea that not only may make that an invalid statement but possibly the reverse that
"thin lip players should consider a larger mouthpiece" have perhaps a little more validity
(my thought is that neither concept is all that helpful but read on...)
Those with thick, flabby lips may have a natural tendency to be able to make the very smallest of aperture hole while still maintaining loose vibrating surfaces. These smaller apertures can thus take advantage of the smaller/shallower mouthpiece cup.
Look at Cat Anderson? He used the smallest piece I've ever seen here: Cat Anderson
Another African American with the typically large lips was Clifford Brown who use what? From our very own T/Master I found:
"Clifford Brown's mouthpiece that used to be marked 17C1 is now marked 10 3/4CW"
Now that's small!
Then on the other hand the person with thin lips may possess a coarser lip texture. So he may need a large piece in order to allow good resonance. His lips naturally more stiff.