I have done this exact same size --both ways and the tube joined wing model was lightest - however that is because the entire model was -piece by piece -lighter -lighter cowl and canopy also
So it's pretty much a wash between the two methods? I would be very happy with a 12lb model using a ST2300, 10lbs is simply amazing.
The dihedral was close enough with the 10% tip and 12% root - and flat along top high point
So it shall be.
Note in the interior shot --the forward fuselage ass'yis an I beam --on it's side - this is incredibly stiff and light made from laminated balsa and spruce longerons .
I'm not sure I have this right. Are you referring to what looks like the fuse floor? It appears to be spruce longerons on each side with an end grain shear web in between, is that correct? Then you simply have a framework to support the covering and form the exterior bottom of the fuse? At least that is the way it looks in the fuse shot from the tail forward.
Many thanks for the 3 view and pics.
Mark