Diahan Southard is a brilliant, generous, and kind genealogist, geneticist, and teacher.
It is because of endogamy in the Jewish population that this tour and her other genetic website tours fall short. The tour courses are totally geared to people without endogamy, to people whose ancestors come from a number of different countries, to people whose mystery matches clearly match a known ancestor, not to Jewish researchers whose known ancestor's mystery matches are virtually the same as another known ancestor's matches, where the paternal side of origin is Lithuania and the maternal side of origin is contiguous Belarus (parts of which were once in Lithuania).
Perhaps there should be separate tours for people with endogamy that could delve into how to best use each site.
The reason I took each tour course was to see if I could learn the maiden names of my 3 2X great grandmothers born in Lithuania and of my 3 2X great grandmothers born in Belarus so that I might be able to find records for them and their birth families. That was my goal. I understood that I would need relevant third cousins to test. I do know of a few definite third cousins, but I had hoped the tours would help me find additional third cousins which they didn't.
I understand the winnowing process of matches where there is endogamy, looking only at substantial longest segment plus additional segments. I took the endogamy course. Yet I have a list of those winnowed matches with no way of telling which of my six unknown 2X great grandmothers each matches because virtually each matches all.
I will try to look again at the possible third cousins to achieve my goal. The materials for each of the site tours was repetitive which would have been fine if I did not have endogamy.