I have a problem. I am the sound tech for a church. We meet in a 1000 seat auditorium. We have a full band (electric guitar, acoustic guitar, bass, drums, keyboard, lead vocals, 4 backup vocals, a choir of about 10-12, and 4 on stage monitors). Basically a rock band with a choir. We have run out of room on our board for everyone in the choir to have their own mic. I need to mic the choir with 1 or 2 mics. I have experimented with inexpensive overhead choir mics and have tremendous feedback problems. It has been suggested to me to try an SM81, SM137 or KSM141. I am on a budget but not too tight. I just don't want to spend $200-$300 on a mic that I can't use effectively.
In short, you have hit a brick wall and the wall is made of the laws of physics.
Distant miking of a choir using two or three mics is not possible in a loud "rock and roll" church environment like yours. To understand why, read the article "Understanding Sound System Gain and Feedback" available at: Click here
Read the article carefully and work through the numbers. You will quickly discover that for your choir to be "loud enough" to be heard over the band, close miking is a necessity.
Save your money for any type of mic placed at a distance. This technique does not work in a loud music environment like you have.