For the record, a single source consisting of two microphone channels is capable of producing sublime stereo recordings and is the right choice for most tapers. Call it two sources if also recording SBD, but lets ignore that for now.
More than two sources is a great way to compare things, and can hedge the bet / improve the odds by providing a choice between those sources.
What the incorporation of more channels in a single source can do is: Hedge the bet / improve the odds; Allow for a greater specialization of what the pairs or individual channels are providing, such that their sum is greater than any of the individual parts; Provide what is needed for playback using more than two channels. Most tapers have no interest in the last one, but the other two may be of interest.
I've posted many times that for most tapers that want to run a single-source consisting of an array of more than two microphones, I think the sweet spot is probably four mic channels total. What makes that a single source instead of two sources is when those four channels are specifically arranged to work together collectively in combination. Two stereo pairs on the same stand or mic-bar, each designed to work well on its own, constitutes two sources, the combination of which may or may not work better than either on its own.
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This is the essence of the distinction I'm trying to make.
Additional microphone channels beyond four in a single source can certainly be beneficial, else I wouldn't bother doing it or posting about it at TS, yet will often be a case of diminishing returns. Properly arranging things so all channels work together optimally gets increasingly difficult. There is more stuff to haul and setup. There is more one needs to do afterward. Managing it all gets more complicated. All of that limits the suitability of using 6 or more microphones in a single source to a much smaller subset of tapers, which is all good and as it should be.
Each taper gravitates to whatever methods work best for them. We're a small community, fertile with individualism and creative solutions, and are fortunate to have this place to share and discuss these kinds of things. Making these kinds of distinctions is important to me for thinking about arcane concepts involved in taping and discussing them with sufficient clarity. To each his own. Make great tapes in your own way. Thanks to everyone here for sharing their thoughts, ideas, and recordings.