After lots of (re)alignment, we riveted the piano hinge to the elevator. I learned a lesson here: It's better to rivet it into place starting at the mid-point and working outward. Else, you can introduce a slight bend in the hinge that effects the hinge rod's ability to seat into the hinge halves. If that happens, you actually have a bow in the hinge that can effect the trim tab's up/down swing.
After all my effort, I didn't quite get the trim tab's and elevator's trailing edge flush. I'm told by my area 'experts' not to sweat it....to not let perfect be the enemy of good. I can do that.
Tomorrow, we roll both elevators' leading edges, mount the bearings, and check the balance.
