Hi, Murray. Not to put a damper on things, but before you spend too much time on the categorization effort...
I'm chiming in only because you wrote that your purpose for a D1 mtDNA category is "to identify the descendants of my 7th great grandmother," and it won't be able to do that; in fact, simply carrying D1 mitochondria won't be able to genealogically associate your 7g-grandmother to anyone.
Consider that even if Marie Boudot was haplogroup D1 (and that alone would take some work to demonstrate, notably a triangulation among living descendants who have very solid paper trails that far back; there's currently no description of mtDNA findings on the WikiTree profiles of Marie or her two daughters and, given that the earliest known ancestors shown at FTDNA projects are self-reported by test-takers and often incorrect, I don't see any research delineated on the Quebec mtDNA project site that investigates those Louise Boudeau/Marie Boudeau lines), simply locating others who are also D1 would provide no correlative association of a genealogical relationship. And after that staggeringly recursive sentence :-) it's also worth noting that in the results table of the Quebec mtDNA project only HVR1 and HVR2 variances are shown (I assume differences from the RSRS). One of the two defining mutations for D1 is C2092T, which is in the coding area, not the hypervariable regions. In other words, some of those people grouped together may not even carry the same subclade of D1 and therefor not be related in the genealogical timeframe...but we can't tell from those data alone. For example, all the variants defining D1a, D1b, D1c, D1d, and others exist in the coding region and are not examined by the HVR1 and HVR2 tests. It requires an evaluation of mitochondrial full sequencing to determine the subclades, some of which themselves are thousands of years old.
Under the current Phylotree classifications, D1 is a high-level subclade under D4, which in turn is only one of two basal branches of haplogroup D. There is very little diversity in human mitochondrial DNA to begin with--for genealogical purposes, anyway (shoot, our modern human mtDNA differs from that of the Neanderthals by only about 200 DNA "letters")--and the D1 haplogroup is just too old and too widespread for any conclusions about shared genealogical ancestry to be drawn from the haplogroup alone.
D1 seems to have appeared between roughly 15,000 and 17,000 years ago (Kumar, et al., 2011) and it's found today throughout almost the entirety of North, Central, and South America. There are several million people, maybe tens of million, who are D1 or one of its 39 subclades. Interestingly, however, if you look at the heat map Roberta Estes provides in her 2 March 2017 blog post, it will show that there are gaps of D1 saturation in North America, and that the geographies least likely to show D1 populations are in the northeast where, evidently, Marie Boudot was born, lived, and died. The highest concentrations of D1 are in what is today Brazil.
That said, if it's possible to determine with a degree of certainty that Marie Boudot was D1, then that could be used as strong negating evidence in hypotheses where folks show on paper that they are matriline descendants of Marie but they don't test as D1. In that case, the absence of the defining mutations for D1 would indicate an error in the paper trail; they would all have to carry the D1 variants. But since millions of people in the Americas are D1, using that as a form of positive evidence becomes difficult, and requires that a thoroughly documented paper trail be the first priority for each person tested.
