I've built and flown many airplanes of this size in the past. The key is to make them as light as possible. I will add some 1/32" liteply pieces at the front and back of the spar between the inner four ribs. Since it is so thin, it can be bent across the dihedral/sweep break without dividing it into two pieces. That should be more than enough reinforcement.
I'm not planning to add any type of gyro. Again, keeping it light is key. I also have a micro helicopter that I fly with the camera, without any electronic stabilization except for on the tail, and this will be a piece of cake compared to that. It will require nearly-calm skies, though.