Fuselage sides are made of 2 ply of 2.5mm (3/32”) balsa reinforced with a 0.8mm (1/32”) plywood. There are also open bays in the back which looks to be a little weak. I will use one piece 3mm (1/8”) balsa sides that are reinforced with a layer of 100 grams glass cloth. So the thickness of the sides will be less than the plan. This means that the formers should be a little wider compared to the plans to save the outer width of the fuselage.