Profiled mating surface left lower Winglet, mostly with 2" sanding drum. Glued on with urethane bond, secured with hot glue blocks and mixing sticks and wedged bits of glued foam in the gaps.
Cleaned up right Winglet join, and tried fitting 1" square wing foam fillet shaped with a sanding drum to lower join with urethane bond, from the shear web to 2" aft of the trailing edge.