Should there be a piece of balsa on the rear of the hatch? One can see right through to the verticle stab.

I covered the hole with black paper glued to the back side of the hole.
Looks finished from the outside, adds no weight or length to the canopy as a piece of balsa would, fits perfect.

Never thought of paper. Will try it tonight. Thank you.

Just remembered, after I put in the paper I masked off and painted the inside of the canopy including the paper to get it all the same shade of black.

Yea, I had figured on painting it also. Want to change it to a grey or something similar.
Hopefully that will keep the heat down a little and prevent canopy warping. Hot and humid
down here most of the year. But at least it doesn't snow!!