The plan shows a single center rib made of 3/16 balsa, but I opted to provide two 3/32 balsa ribs for the root instead. Use the provided dihedral gauge to tilt the root ribs to the correct dihedral angle.
Rather than the single dihedral brace shown on the plan for each spar, the kit includes dihedral braces for front and back of each spar.
I also changed the firewall to 1/8 birch plywood instead of 3/16 because it cuts better on the laser cutter, and a plane this size doesn’t really demand 3/16 ply anyway. Please note that the firewall is not square. It is taller on the right hand side to allow for the three degree right thrust called for on the plan.