Yes, light weight is important in rubber powered and electric powered models.
The other thing you will need to do is double the elevator and rudder spars (as well as the aileron outlines if you want them to function) so that the control surfaces can operate independently. The traditional method to hinge them is to take several strips of 3/8" X 3/4" cloth and glue one end to the upper side of the stabilizer and the other end to the bottom of the elevator. Glue the next one opposite and duplicate on the other side.
Note the control horn which you will need to add so that your RC servos can actuate the surface.