After both the analysis of the Ur-Matriarchy and the discussions regarding the restructuring of the dissertation project, I have begun to think about the Braudelian Longue Durée as the moral equivalent of a petitio principii, in that in many instances, including some that Braudel applies in his book on the Mediterranean, the unchanging nature of the historical structure is assumed rather than demonstrated, thus undermining the quality of the argument.
Furthermore, as the micro-historical turn would suggest, a detailed analysis of the assumed longue durée would discover both variability within the structure across time and would suggest less Procrustian research paths whose questions cannot be suggested up front; more research into Danto's observations regarding the "Monassian rule problem" is required to firm up thinking here.
Thus, it might be that the trichotomy of longue, médian and court re-collapses to the distinction of event and structure well-attested with German historiographical tradition (e.g. Reinhart Koselleck). This is not to deny that post-facto of the historical reconstruction, the structures can be sorted temporally by their duration, which is independently useful, providing terminus ante and post quem information. But unless the work has been done up front, it cannot be presupposed for the argument.
Rather, the claim will have to be weaker, i.e. that in a specific historical reconstruction, a specific structure turned out to be temporally stable across a long, medium or short range of time--with no claim how that would play out in alternate settings, reconstructions, in the future, or for even the same topic assuming additional research work. It is an empirical argument, and can be swayed by a single counter example, not an analytic category. It is a werksimmanente Eigenschaft.
As a research strategy, it will be permissible to assume that a specific temporal structure might be of long duration, but that has the quality of a heuristic and not of a binding assumption.
Furthermore, it stands to reason that the longer the duration of a temporal structure, the higher the probability that its duration will be invalidated by an event.