In all this discussion of ideal cavities I don't see much mention of sun and wind exposure or elevation, yet in my experience these things can be very important and probably more important than the nature of the cavity, assuming that the properties of the cavities fall within normal ranges.
As for insulation, one of its principle functions is as a windbreak and seeing as it's usually black it's ability to absorb and radiate heat.
Beyond that, has one writer mentioned recently there are so many variables that there is probably not one solution, but many.
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