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
typically the CAPS I did this size are 10lobs with a YS140 and 13 with a ZDZ40 and can
I also flew the H9 80 " setup with a ZDZ50 and a in cowl setup I designed - very good flyer but almost 3 lbs heavier
The dihedral was close enough with the 10% tip and 12% root - and flat along top high point
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 .