[John G Macalla]

I've built this one once before 50 years ago and finished it. However, this second time I'm baffled on how to start it.
With the outer skin tube glued and the formers installed, positioned and glued, how do you install the 2 wing spars? The centers of the spars are to tall to fit into the side slots. Please don't tell me to have to install the spars before gluing the tube together. There is a solid line on front edge of each of the slot openings that extends further downwards than the rear slot edge. Do you cut this deeper to make a somewhat flimsy flap and force the spar thru then glue the spar into position and the reseal the slit? Looking for help before I botch this up.
Secondly. Is there a preferred tool for cutting curvatures out? Xacto knife, scissors or something else now days?