I went to the big box store and purchased a piece of their 4' aluminum angle to use as the aileron alignment tool. A line is dran on the center of this tool and is drilled with two holes (along the center line) that are matched to two holes on the outer wing rib. When the tool is attached to the outer wing rib, it shows you what the ileron needs to match up to so as to be on the centerline of the wing trailing edge. This is important that the ailerons line up on center because the flaps and wingtips are also set to center on the ailerons.