Very neat work Donny! Wish I could think of such solutions myself. (btw, what do you use to stain the wood such a nice antique hue?)

Don, you've probably seen this before, but for the sake of the thread:

On my EIII rudder I used laminated ply strips.

The approach is probably more laborious than Donnys.
As with the nieuport rudder this doesnt' have many ribs to support the structure so lamination is best to get the frame very stable.
I first cut a template and wrapped the strips around keeping them in place with tacks/ at one end they're held by a notch (arrow). As it was already rather late in the evening when I started I decided to use white glue and let dry over night, didn't regret that, it is extremely rigid.
the ribs are capped with very thin ply that overlaps onto the frame, this improves integrity even more.

Anyway, pictures are better than words: