I'm really liking what you are doing ,my friend. I suggest you add booms to the tails and perhaps a jet engine pod as seen on German late war concepts. In fact,I would have mounted it behind the cockpit on a pylon. As to the flimsyness issue, I would have used a full length strip ,top and bottom,on the joins and if possible, taken one and glued it then trimmed it ruffly. I would add the other side to it. Once dry,I would clean and reshape the edges to shape. This would thickened the wing but given maxium strength. I use this method all the time. Can't wait to see this finished ......