Adding to Moke's comment, the 90 degree angle with a pair of directional mics helps to create the stereo effect. Stereo effect is created by differences in both sound pressure and timing of the same sound reaching each microphone. By angling the mics (in the case of DIN and NOS, the angle is 90 degrees), you create a sound pressure difference between sounds arriving at the mics in the horizontal plane.
So as Moke said, AB is used for split omni's because, since omni's aren't directional (i.e. their pickup pattern is circular), there isn't much of a sound pressure difference between the two mics. The majority of the stereo effect you hear in AB recordings is a result of the difference it time it takes for a sound to get to one capsule versus the other. Obviously, in this situation, if two mics are positioned close together that difference will be less pronounced than if they're farther apart. The rule of thumb is that omni mics need to be about 30cm apart before you're able to hear some stereo effect.
With directional mics, you can create the stereo effect with both timing and sound pressure differences. Since your directional mics are also spread apart, you'll have the same timing difference as you have with the same spread with omni's. However, you can pronounce the stereo effect by angling the mics so that the mics are pointing in different directions. When doing this, sound is entering the front of one capsule and the side of the other capsule. The pickup patterns of a directional mic is more oval shaped, so the sound level entering the side of one of the mic capsules is a few db lower than the sound coming into the front of the other capsule. When listening back, we hear these differences and that helps us directionally locate a sound on a recording as coming from one side or the other.
The analogy of course is your ears. Both ears point in different directions and they're spaced by 17 or so cm (not uncoincidentally, that's ORTF and DIN spacing). Our ears don't point straight forward, so our natural hearing also relies on both sound pressure and timing differences for directional sound location. Lots of people like their recording to reproduce what they heard at the show, so ORTF and DIN (or DINa) are probably the most popular configurations since they replicate the spacing of your ears.
Sooo, if I remember correctly, your mics have cardioids in them. Because of the above, I'd recommend using the NOS configuration over the AB configuration. (I'd personally probably go with DIN or DINa, but that doesn't appear to be an option for you tonight. NOS tends to be preferred when you're closer in to the sound source.)