With a high school band (unless you go to an arts high school where people actually care a lot), there's no way you're going to get them all to go home and pick out their parts from the cd. It's just not going to happen. Trying to approach any ensemble like that without your shit 100% together (sheet music for each part, full score, thorough knowledge of the piece, etc.) is pushing it....to try that with a high school level group is flat out unrealistic.
Don't get me wrong, I'm not trying to burst your bubble and I think it would be cool if you actually could pull this off, but I can almost guarantee you that you're not even going to come close with the approach you are using now. Good luck though!