An excellent tune for both dynamic range and also featuring loud Glockenspiel and piercing Xylophone is a piece of library music called "Grandstand" by the Keith Mansfield Orchestra. I now use this as my test tune as overshoots are very easy with this tune if not controlled, also it has a very full sound and great stereo field.
This may be very hard to get hold of legitamately so if you need a CD rip of this one I can send it to you.
As it’s library music, this is legal as fees only need to paid if used in a production, or broadcast.