The famous Mercury recordings were made with a three mic spaced array recorded to a three track film recorder not a stereo pair.
In this case you should be ok with a pair above the conductor. I would however put up mics for the chorus. Depending on how good they are (or not) without them you could be struggling. Ideally four matched mics would be best, but looking at your list I would go for a cardioid pair in the centre, (ortf, XY, whatever you like) and another pair as outriggers. If you use only a pair to "spot" the choir you could end up with them sounding like 20 or less, not the 40 you have.
Having looked at your list, I'd be using the AKG's for the orchestra, and the TLM103,s and KM84 for the choir, but thats my own personal choice.
Regards
Roland
