You'd think it would be easy.... Just put the wingtips in place, make sure they are in line with the bottom of the wing, match drill, and done. But.... they didn't really line up the same way twice when I marked it with a Sharpie, so I ended up using the strap to hold the wingtips tightly in place, then drilled a hole, then put in a Cleco, then drilled another hole, then put in another Cleco, etc. That worked fine when the wingtips were inside the aluminum skin. For the trailing edge of the wingtips, though, the aluminum is on the OUTSIDE, so I borrowed a "strap duplicator," aka a hole finder, to locate the holes and drill them. Then back with the Clecos. I was planning on mounting them now, but I wasn't sure if I'd need to get in there for access to the landing and taxi lights. The decision was made easier, though, when I realized that I couldn't put both wings on the wing stands with the wingtips and, more important, the winglets at the end of them, in place. They run into each other. So, the wingtips and winglets stay off until the end.