Wow, a "living encyclopaedia". I suppose that's better than "a national treasure", which would make me feel really old. All I know I have learned from books, especially good old George Gourlay the Anstruther newsagent and bookseller, whose "Anstruther: or Illustrations of Scottish Burgh Life" (1888) mentions the Black headstones in Anstruther Easter (St. Adrian's) churchyard. The oldest one is the headstone of William Black, who was "prćses" or chief magistrate of the town. According to the Scottish Genealogy Society pre-1855 MI of East Fife volume, re Anstruther Easter churchyard, he died in 1637, but Gourlay quotes the Latin inscription in full, which makes his death 20 years later. He was supposedly 56 in 1657. Gourlay would have seen the stone when it was less weathered and illegible than it is today. And Gourlay mentions a John Black on the Anstruther Easter town council in 1662. I assume these Blacks were ancestors of the 18th/19th c. ones. Towns like Anstruther were run for generations by the same little self-perpetuating cliques.
Stephanie Stevenson's "Anstruther. A History" (John Donald, 1989) was specifically written as an updating of Gourlay's book and she also mentions the Black family. On pages 130-131 she tells us about the records of the Sound Tolls paid at Elsinore in Denmark by vessels sailing to Danzig and Königsberg in the eastern Baltic and "Among the shipmasters were Alexander Black and William Black [of Anstruther] (he was a commissioner to the Convention (of Royal Burghs) in 1597, 1601 and 1603 and just over sixty years later other Alexander and William Blacks were commissioners for the burgh)."
Stephanie also mentions the Johnstons, builders of Johnston Lodge in Anstruther, a historic house near the harbour in part of which she lived when writing the book. I'm not actually sure whether the Johnstons of Pittowie were identical with the Johnstons of Rennyhill in Kilrenny. Further research required.
Harry