Jon wrote in post #2389905
Nifty. And chimp the histogram the first several shots; unless you're very close up, you'll probably have some of the off-stage area in the frame and that'll encourage your camera to overexpose the choir in the center.
Just a couple more thoughts...
I suggested spot metering off of his nephew using the spot meter, but I didn't mention to switch to manual after that. What I do is spot meter (even partial spot metering works well enough for me for sometimes the spot meter will over expose if it picks up dark parts of the face!) for the first couple shots off the people I am shooting (assuming they are in the same light for the duration of the shoot), look at the exposure that yields the people properly exposed per the histogram, then change to manual based on what settings exposed right, then go from there. I usually end up from the church with 1/160, f/2.8, ISO 1600 with my 24-70 or 70-200, both 2.8s.
As long as he gets his nephew properly exposed, it won't matter about the rest of the stage because some will be exposed over and some under. With this, focusing and composing the shots are the only aspects to consider. If the lights change often, then aperture prior on the widest aperture is the best route, IMHO.