As yet I do not know where in the world he is. I have emailed him and await a reply. It is just possible that a comparison of the paper trails from our respective family history research may reveal a link between us. At least we may be able to eliminate a common ancestor over a few generations. FTDNA has calculated the percentage chance of a common ancestor for Mr. Smith and myself, a particular McIlhagga, depending on what is called the Genetic Distance between us, shown I gather by the mutation rates of our particular genes.
There is apparently a 37.69% chance of finding a common ancestor two generations back, a 61.17% chance four generations back, a 75.81% chance six generations back, an 84.92% chance eight generations back and a 90.61% chance ten generations back. Their calculation goes back 24 generations when there is a 99.66% chance of a common ancestor. My great-grandmother was a Smith but at present I can't see how that is relevant. I only have four known McIlhagga generations in my line (back from me) so I suppose those can be eliminated. Five generations apparently takes me to a 69.35% possibility of a common ancestor. I wonder what Mr. Smith's paper trail will indicate?