Actually Gen. Patton was of Scot-Irish & English stock. Born in San Marino, Ca (local SoCal boy). Eisenhower was of German stock, from Kansas. Roosevelt was of Dutch stock. Never go by surnames, can be very misleading here in America. Was a former pro football player with the name of Donovan McNabb. Scottish, Irish?.... no, he was black. Remember that Hitler called America a mongrel nation and would never be any good if in a war.
WASP (White Anglo Saxon Protestant) are considered from a English blood line, for the most part. Anglo is the older word for people of the British Isles. Saxon, of course, are rooted in northern France. But after 1066 ad (Battle of Hastings), blended with the native English blood. Because the took over that country.
Your wrist measurement would certainly suggest a small bone frame. Zane had a smaller frame also. I would still believe that a 16 1/2 arms could be within your potential, judging by your photo anyway. That once 46 1/2 chest measurement could be the first clue to any potential you may have. But you will have to attempted to gain more pure muscle mass. Not to be critical, but recent picture of you show almost a unhealthy body. One that most men may not want to copy. Good Luck
Side Bar: just to note, most men who claim a 17 1/2 or 18" plus arm are really in the 16 1/2 to 17" range. Tend to pump up before the measurement. Want a true are measurement. than take it the first thing in the morning (no pump). And with a narrow steel tape. Want a really, really true arm measurement...take it first thing in the morning, with the arm hanging down, along side of the body. A real ego buster for most men.