More "research", lol, in case there are any technical geeks out there like me that want to know more useless information.... I acquired a reproduction 1950 Fender catalog which lists only the Esquire guitar and Mapes strings. The Electric Spanish Guitar strings are Mapes Set No. 1100, with Anaconda ball ends (referring to Anaconda American Brass); probably monel alloy round wound, wound 3rd, over hex core, ground and polished, and probably 13-55 gauges. Going to have to get me some half rounds or brite wires! I don't think the Martin Monel strings are hex core and they certainly aren't "ground and polished". EDIT : The Mapes sets offered a plain 3rd option according to this catalog!