Tim,
a "later development" detail for the Vertigo was to add 3/4" to the tailpost (chordwise). I did this on mine and I recommend it. It adds a little fin area and moves the rudder hinge line back away from the elevators. I used balsa. Maintain the same thickness I.E. do not taper it aft or your rudder will be too thin.

Looking good so far.
-Robert