The current website for Robinson’s seems to be
http://robinsonsharpshop.com/strings.html. I also have a 32 string J. Witcher, made in 1976, strung G to c and am looking for strings. You can still reach Mr. Witcher at Witcher Harps (there is no email address listed, but he does provide his telephone number). He was very helpful, and read me the string chart for my harp over the phone. Now, I just have to track down someone who has nylon in 0.029 and 0.026 diameters…