I finished installing the root doubler tonight. My strategy of taking each skin off at a time to use as a template, then using the overlapping hole to continue the next skin worked perfectly, tonight I did the holes through the lower aft skin, then trimmed the end of the doubler as per the plans and installed everything back on the wing, the doubler sits perfectly flush on the skin, I'm very happy with the result and no hole duplicators or other special tools were required.
