The "skin" and style of foam is secrete as it has never been used, so we have to now show you some hard hits/landings to prove the quality.
Ok Ok me first,I guess a .010" - .020" polycarbonate sheet that is thermoformed in a mold and then back filled with a foaming polyurethane adhesive. Maybe after some structure (linkages etc.) or hard points are placed.
Actually the skin can be thinner to allow for direct printing on a large format commercial machine.
Sounds like it maybe advantageous to setup the TE for full span hinging to allow a simple DIY mod for adding flaps (include provision for a servo).
As for rudder,though not absolutely necessary,make some method of providing a not to problematic manner of adding it in. DIY.
In the mean time,how about some up close/detail photos of your TR?
Just think,in a few years we can all say...we we're there
Skies and fortunes to you fellas.