Originally Posted by zypod
Thank you everyone this has been a great help.
Firstly yes my plan was to sing in the performance as well so I'd have a sound check then press record and run over. I'm interested in the M/S spot for the piano although i've never used a M/S spot in this application before so I wouldn't know how I would mix it. I was thinking of setting up the ORTF pair first then seeing if I needed an ambience mic or if I should just use the cm47 and ribbon on the piano.
I will post some audio clips next week
Just remember that for purity and thus clarity, both of image and intelligibility, less is more. Every time you put up another mic you confuse the phase and the image. ORTF by itself is definitely the ideal. If you can put a small head sized baffle between the mics, you'll take care of the undesirable phase issues generated by the distance between the ORTF pair by shadowing the frequencies shorter than that distance.