I am assuming that you are talking about a string quartet--
The Brauner and Coles are somewhat tonally disimilar and would not be my choice for MS. In fact, MS would not be my choice.
I would either try omnis with a Jecklin or subcardioids (preferably Schoeps) in ORTF. They are very smooth and with only 110 degree spread only 17cm apart will not give you a wall-to-wall image.
You could experiment with cardioids if you like that sound......
I touch of something on the cello and you are set!