I love it! Especially the bells! It's so dramatic! The Strings have extrememly nice parts too! Very Berlioz! But the brass! That was just legendary!
The theme was fantastic! Very foreboding! The dissonances were just perfect!
I love the "happier" parts with the very high string bits, very nice contrast.
There is one part with two points of silence that I think could have benefitted from a constant tremolo pedal in the bass. Somewhere near the 8.. something mark...
The longer quiet part around halfway through the 11 minute mark's part is too quiet I think, it's almost like silence.
The only other thing I would change is the number of staves! It's a bit big when you have one for each instrument!
Over-all, I absolutely adore this piece! It's fantasticly done and I didn't think any part sounded "weird" with the orchestration as you stated in your original post, though that's just me!
The melodies are so beatuiful and the atmosphere is absolutely perfect! If I were you, I would be extrememly proud of this fabulous piece of music!