Transposition in Orchestral Scores
ohhh i know what you're talking about...
the players of those Bb or Ab instruments use the same key signatures as we do, except for the fact that they are trained to read a "C" on our music as a Bb or whatever... I think that's the way it works, they look at a 3rd space C for example, but they play it as a Bb on their instrument...
i dunno, anybody in here play one of those instruments?
The best thing, imho, is to talk to your music director, and approach him intelligently as he doesn't shoo you off as some amateur wanker, and approach him with this question. i'll also ask my musicianship teacher (Prof Bill Westcott, gonna see him tomorrow in class), and see what he says. I'll give him a sample piece of music, and ask him how to write it for different instruments.
better yet, email me a sample of the music you want to use, maybe a couple bars or lines, and i'll ask him how to do it, and i'll give it back to you written for the other instruments.
i think all it takes is practice to adjust your writing style from centering on "C."
write the C major scale down on a piece of notation paper, but then think of it as a Bb or Ab (whatever the instrument is you're writing for) major scale. then change the key signature around (add flats or sharps) to make it "C" or whatever key you want. for them to get to think of their blank key signature major scale C, you'll have to adjust their key signature (which is generally blank for Bb or Ab or whatever their natural note is) for them to get it in C, like how we'd change our key signature around to get into Bb. Just think backwards, i guess. For them to think in "C", they have a key signature with flats or sharps, and for us to think in Bb or Ab, we'd have to add flats and sharps to our blank key signature to get it into that key.
now i *THINK* i am right (as i usually think i am), but check around and ASK YOUR MUSIC TEACHER or the conductor of the orchestra.
congratulations btw, on the opportunity and the best of luck... you're living my dream and i think its totally amazing what you're doin. tell me how it goes, alright?