...i've been using the Raschers top tone book, which for me worked very well.....apart from some of the actual altissimo fingerings that dident! i think maybee becawse i'ts more for alto rather than tenor?
I found the altissimo fingerings on the Pete Thomas site much more user friendly! but again i found i had to alter some to suit...
I used the Rascher book too - it works, with varying success dependent on your technique, and your sax!!
Different horn designs have different effects on the altissimo, and yes, different members of the sax family have slightly different characteristics when working up there.
Really you're working a little like a trumpet - your chops make the notes, the fingerings just alter the intonation. I find Rascher's fingerings work better on my tenor than on my alto (need a new alto for that reason) and still worse on Bari. Of course this could also be because I play the instruments in different proportions in general, tenor most, then alto then bari...!
So yes, I've tweaked the fingerings a bit, but the way I read the intro to the book was "these fingerings only work if you get the embouchure control right". Even then, since everyone's embouchure is different, you may need to alter things to suit, since Rascher's suited him on all saxes!
I think what I'm trying to say is, if you can find it, there's a compromise to be made between embouchure and fingerings which should work for you on any sax with varying degrees of ease. But some horns are more suited to altissimo than others!
Nick
P.S. Great resource by the way, I'll have a good luck through when I go back 'to work'...!