Not sure if anyone cares, but this is a good opportunity for me to further the explanation of my line of thinking about "stereo" in this way, and in particular these kinds of less-than-typical microphone configurations which spring from that line of thinking, designed with the intent of optimizing for the aspects of a recording which are most important and I want, given the constraints we are required to work around. In other words- thinking more in terms of "Direct/Reverberant", "Front/Back", "Middle/Sides", and how some stereo requirements change by frequency range, rather than thinking in terms of "Left/Right".
Imagine we're recording outside, say in an amphitheater. There is a PA, and we can setup pretty much were we'd like, but no SBD access, no on-stage access, and I'm going to record from a single location out in the audience. My two channel starting point for that is a pair of spaced omnis, say 3' apart. From there I add a center directional mic which directly addresses the two primary problems I hear with spaced omnis: It provides a far greater overall forward bias and "presence" (Front/Back, Direct/Reverberant stuff) because it is pointed so as to reduce pickup of everything but what is directly in front, and also provides a strong, solid center which allows for an even more optimal spacing of the omnis without getting a hole-in-the-middle. To my ear that greatly improves upon the spaced omnis alone- sort of like teamwork, the addition of the forward facing center directional mic allows the omnis "do what they do best" and provides the ability of adjusting for the optimal balance between the omnis and center after I get home, which is a huge advantage.
I'm completely happy with those recordings, yet in search of sharper stereo imaging (which is important to me, but further down the hierarchical list of what is most important) I add the pair of supercardioids. I space them ~2' or so apart and point them directly to the sides, forming a three-mic array with the center directional mic. I choose that arrangement because I want to maximize the level differences between the signals of those three directional mics, while still keeping them in a viable stereo configuration. That 180 degrees supercardioid angle is going to produce the greatest channel separation possible for sounds arriving from angles which approximately line up with the left and right speakers on playback. The null angle of each supercardioid pattern points approximately 45 degrees off center to the opposite side, which more-or-less lines up with the opposite playback speaker as well as more-or-less with the opposite PA speaker in the venue (opposite edge of the SRA in Stereo Zoom terms). Not exactly, but close enough. Sound arriving from that direction will appear in the signals from near-side supercardioid and the center mic, but will be minimized as much as possible in the supercardioid channel on the opposite side. (Farther off-axis than that, say fully to one side or the other, the inverse-polarity back lobe of the opposite supercard comes into play somewhat, introducing some anti-phase information in the channel opposite the sound source which is probably useful as well).
I retain the wide omnis, which are my fall-back starting point anyway. As omnis, they compensate for the reduced low-frequency response of the supercards, and their wide spacing provides excellent stereo bass which a more narrow microphone spacing does not. They also contribute to an open and "airy" stereo ambience and sense of space. I now have 5 mics in the array, arranged to work optimally together, in a way which minimizes potential conflicts between them when their signals are mixed together, and provides even greater flexibility when I'm mixing to 2-channel stereo.
In a surround playback environment, the channels stay discrete instead of being mixed, but are still level balanced to taste afterwards for best effect. The supercards are routed directly to the Left/Right speaker channels, and the center mic routed to the Center speaker channel. The omnis get routed to the Surround channels (possibly with their bottom octaves mixed into the front Left/Right speaker channels to take full advantage of their deep stereo bass contribution).
Moving into a less ideal recording situation, say much further back or in a more reverberant space, I'd start pointing the Left/Right supercardioids more forward while increasing their spacing to compensate for the narrowing angle between them. That's going to reduce the optimal channel separation somewhat, but increase the forward pick-up bias of the array and reduce sensitivity to reverb and ambience from the sides and back. That's a trade off I'm happy to make because if I can't have both, I value getting a good direct/reverberant balance far more than super-sharp imaging.