I have been setting up around 10ft. from the stacks and using a DIN Config that isn't precise by any means, but is more of positioning the stacks and the mics to be pointing at each other the best I can.
I have been using hypers also and it sounds like I am doing the same thing you are thinking of trying, but I haven't had any bad recordings...actually my last recording from 12-4-04 is my best so far.
I am not sure about the possible distortion with MC012's since I haven't run them before, I have been running Grider's AKG 480 hypers.
My question was more one of whether or not it would be a good idea to get real close to one of the stacks and ignore the other one since a diagonal setup in a corner makes it difficult to be in the center of the stage in the venues I have been taping at that are long and narrow. It seems to me that the difference shouldn't be great as long as the band is running mono of course!
Hope this helps.
Ron-