No, I haven't. I corresponded with him for about a year back around 1985-1986, but then my life sort of went haywire (including the birth of my daughter), and I lost touch. I hadn't even known when he was (as I as later informed) in this area doing research for his biography on HPL; I'd love to meet the man, but whether it will ever happen or not... who can say?
I will say that, from that correspondence and a very brief bit just in the last month or so (over a possible influence on one of HPL's tales), he is very generous with his time and encouragement.....