Don't do it!! I Have a Pair of them, they are unusable for Choir or Vocals, they seem to me to be the worst buy I ever made after I listened to my Vocalrecordings made with them Years ago. Today we use to record the room of drumrecordings. They have very few highs, but a clean, strong bass, i record also Contrabass withit, but never Vocals.
I used C-1000 Years ago and I never liked them on Choir.
If I would record Choir today, i would try my new Audix SCX or Neumann KM 184.