Ed, here's an idea for you,,,
Grab a 1/16 x 4 x 36" or 48" sheet of balsa. Lay the fuselage on top of that and trace it out. Then cut and sand the shape to your liking's,,, now you have a pattern to make as many fuselage sides that you can handle,,, making the bulk heads is just as easy too
Don t forget to allow the required dimensions of the fuselage. Meaning, it will be a little smaller at the high point of the fuselage(normally at the TE of the wing) due to the sheeting on top and bottom and/or with the wing
As for the wing saddle,,, use a scrap piece of wing with some 220 sand paper glued onto the bottom with something like 3M spray. By doing that, you'll have a nice wing saddle shape, after sanding, for when or if you pot that wing of choice to the fuselage.
In the pic here is what I use to use,,, a piece of a vortex wing