+1 for ORTF. We recorded the Liverpool Philharmonic String Quintet and Flute Quartet a couple of weeks ago using this technique (with Neumann KM184) and it turned out great. Really nice detail and balanced spatial imaging. We also used a pair of spaced omni's (DPA 4006) up on the balcony/upper circle for ambient pickup, which worked well in bringing a sense of the recording space back into the recording as the ORTF pair was a little 'dry'.
We also used another DPA 4006 for an accent mic on the cello, in the end we didn't use it as the ORTF was more than enough. Although it was nice having the option. Make sure you delay any accent mics back to your main stereo pair.
As far as dynamic range goes, just try and setup before any rehearsals on the day if possible and set your gain accordingly. The one thing to watch out for is any applause, so maybe err on the side of caution with levels if you've only got one shot at it. Rehearsals were also a good chance to grab some room tone after the musicians had finished to help with editing afterwards.
If you can I'd really recommend getting hold of a copy of John Eargle's book "The Microphone Book", really great advice on recording Classical Music and plenty of tips throughout.
Hope thats of some help anyway.