RE: Siemens-Schuckert D.III 1/3 Scale
The elevator and rudder are built up from 1/2" stock and do not get covered with sheeting. The plans call for using strips of balsa and laminating them around a form for the perimeter. I don't like doing that so I made curved end pieces from 1/4" balsa, laminated flat. I traced the pattern using SeeTemp material.
I decided to use 1/2" dowels for the leading edges of the fin and elevator because I'm going to make scale-like strap hinges. The fin and elev also get sanded to an airfoil shape
The rear corner of the elevator is a potential weak spot, so I cut a strip of 1/64" plywood and glued it inside the curve. It's now very rigid.