Rearranged the shed, trial fitted the port wing, marked up the rib to rib join which needs trimming this side also for a 1/16" gap, even though it is more like 1/8" at the nose...
Pulled the wing off, and tried something different for the wing foam bit. Clamped a straight edge to the joining surface and packed with slivers of 3/8" H45, with urethane bond.
After a couple of hours break removed straight edge and refitted to bottom, packing the root with plastic packers, (no hard point inboard at the bottom).