Larry, while that looks like a great "fix" it just doesn't seem like satisfying design solution for a WWI model. Fully sheeted tail surfaces? That's just so...well...WW2.
Particularly, for a (light) fabric covered model where all the other structure is readily visible in flight. No PC10 or lozenge to hide such tricks on an EIII. Could you perhaps use CF rod (or tube) for both the stab LE and TE and or cross-bracing between the ribs as seen on the Mick Reeves wing designs?