I got the keyless sax today. The harmonics are quite well in tune. My SBA alto neck fits perfectly (and makes it easier to play). With just a bit of practice I can play up to Bb above the staff, but can't quite get the D above that. I have a lesson tomorrow so I may get some tips on how to approach the higher overtones from my teacher.*
Yes, the Rascherites among us ( I am not one) will remember the picture of Sigurd Rascher holding a Keyless Buescher . He advocated the use of these devices to perform his overtone exercises.
These saxophones have been later on produced in China ( some even have only few keys to facilitate the use beyond the sole overtone exercises the so called “ almost keyless saxophone")