I play several times in the same piece, where I'm the only soprano sax in a 7-member band, a four-bar trill from A to G, lower register. I do alright for about 3 bars, but then my finger quits cooperating and I get slower and lose the evenness. No strategy so far is successful. The part was originally written for clarinet (a Dixieland thing), and I'm sure clarinetists find it easier to trill this with their setup. I don't find trills that hard on flute, piano, or alto sax, but this soprano has me stymied, maybe because it's held in the air and you can't brace against anything? Not sure.