For recording where you want to pick up the room acoustics, place the mics 3 feet apart on two mic stands, or place them on a stereo mic adapter on top of a single mic stand, angled 90 degrees apart and spaced 11 inches apart horizontally. Start with the mic stand 12 feet from the choir, with the mics as high as possible (about 1.5 feet over the head height of the back row).
Monitor the choir pickup. If the sound is too close, detailed, and dry (lacking hall acoustics), move the mic stand a few feet farther from the choir and listen again. If the sound is too distant, muddy, and reverberant, move the mic stand a few feet closer to the choir and listen again. Eventually you'll find a sweet spot with a pleasant amount of room acoustics, but not too much.
If you use omnidirectional mics, you'll need to place them closer to the choir than you place cardioid mics in order to get the same amount of hall acoustics in your recording.