I built an all foamboard version of the Tenet. She flies beautifully and can take some punishment too.
Here are some details on building the fuselage.
Three of these profiles need to be cut out.
Cut approximately 0.7" (18mm) wide strips of foamboard. You can take off all the paper but if you want to keep it, you will have to selectively remove it from the areas that require a bend. Hot glue the strips around the profile. Using a square helps a lot with keeping the strips aligned to the edge. Repeat for second layer. Finish by gluing top profile on.
Another build technique using tissue paper was used for attaching the coffee stirrers to the fuselage and strengthening the wing joints. I did not have good luck using the technique Josh shows where he uses a zip tie to make guides for the linkages. I prefer the coffee stirrers. I hot glued them onto a small piece of balsa then, using the tissue paper you typically get with a shirt, I cut out a small strip, painted it with Elmer's white glue and put it over the coffee stirrer. If you are using FT waterproof foamboard, sand the area first. I typically put three layers of tissue paper down.
This tissue paper technique was used on the wing joints as well.