If you want to capture surround sound ambience, I'd recommend to you to use 2 stereosets instead of a double MS. Because of it's setup, Double MS is not 'really' a surround setup, it's something between of it. If you want to get something wide, take 2 stereo sets: one in front, one in rear.
It's a matter of taste really. My take on this is that Schoeps and Sennheiser are the staples in high-quality, well-engineered field mics. Sennheiser being generally more technically appealing (better specs) workhorse mic (never fails, gets the job done), but Schoeps for the Schoeps sound, which to me is the most well-balanced around, pretty much regardless ...