If you just take one aspect, in this case the microphones, you need to think about how many people there are in the choir, their gender and positioning. Condenser mics are usually the best choice for groups but so much depends on the points I have mentioned above.
Thanks to you both for the responses and information. The choir has around 20 people and I think the majority are women, maybe 75:25. By positioning I guess you mean how they will be grouped? I saw them practice the other day and they were standing in a semi circle/horseshoe, with the men front and center. The second row are slightly elevated.
Adveser, I will look into the things you suggested. Thanks again.