no matter which fingering you use for your altissimo register, you MUST be able to hear the note first, then its easier to hit. Because the altissimo fingereing are different depending on your horn, you, what you've been taught, but Id say make sure you know which note you're shooting for, because I often times you have to lip up or down to get the right oone. Its definately possible to get several notes out of one fingering, but you want to stay with the best one, for you. Once you have the right embouchure in place for that note; dont forget it.