I choose to increase the vertical fin thickness to 1 inch.

You can see here that I ran a Aluminum 'U' channel down the back all the way to the bottom of the fuselage. I then mounted the rudder hinges inside the channel. This gave me the stiffness I wanted in the whole assembly.

All the clamps along the side are holding the Alum. sheet until the glue dries. Yes, the polyurethane adhesive will glue Alum. to wood. Then the panels will be riveted at the seams.