I have flown the twin a lot and have found no need to stregthen the fuse. Mine is holding up just fine. My fuses are however made of a 4 ply laminate of 1/8" light ply from the nose to the leading edge of the wing. Then two plys of the 1/8" light ply to the trailing edge of the wing. Both smaller versions including the twin utilize the truss structure of 1/4" square balsa faced with 3/32" balsa sheet on both sides. This larger version will have the 4 ply 1/8" light ply to the trailing edge of the wing with a truss structure to the tail of 1/4" square balsa and then sheeted with 1/8" balsa both sides. The fuse is finished and I am starting on the wing. The retracts will be an added challenge. Pics to follow.