At least Stuart/Stewart only has 2 real variations. I have one family, McElwaine, that is positively crazy to keep straight. The current line of that family goes by Wayne, but fortunately my ancestor was a McElwaine when she married my Cunningham ancestor in the 1800s. Going back, the family name spelling varies from one generation to the next, sometimes going back to an older spelling. In Scotland, there is a document where the family took ownership of a castle (by marriage). The official English document recognizing the change of ownership has the name spelled two different ways on it. Other versions of McElwaine are Muckelwayne, M'ylveyne, MacIlvaine, etc. If you can think of a different way to spell it, somebody did. Stranger still, they are part of the MacBean clan, but I didn't see any MacBeans in the line going back to the 1300s. There is a Stewart princess though.