After much fussing about the elevator ribs and the elevator trailing edge, I've come to the conclusion that the elevator skins must be trimmed about one inch at the trailing edge. I took out my extra copies of the cradle plans, and there is a precise measurement between the leading edge of th Hstab and the trailing edge of the elevator at each buliding line. That just can't be ignored, and I take it as a design dimension. It sure would have been helpful if at some point in the manual it had just said "Trim trailing edge of elevator skins as required to fit the horizontal stabilizer cradles."
Now this still doesn't solve the rib problem. But I'm closing in on it.