Hi Heiko
Sounds like a pretty decent mix to my ears. The only thing that stood out to me was the timpani roll near the beginning- sounds like the timpanist got left in the Dressing Room! Obviously as it's not purely standard orchestral fare, it's hard to judge exactly how much realism you were aiming for, but having said that, by and large, it has a natural sounding environment. Well produced, interesting piece. Good luck.
Colin