You might try to use both the SE and ribbon on the piano in MS, that way youve got 1 good stereo spot instead of 2 mono spots, which typically don't blend well for this type of recording.
ORTF will work well as your main pickup and maximize the room a bit more than an AB spaced pair would, so you really shoyldnt need much in the way of an ambience mic
Peridot Sound Mobile Recording Service www.peridotsound.com
Originally Posted by Plush
Eventually you should deploy the most expensive and best Mic you can get. It should be hideously expensive.