Thank you for the comment Jose.
At the time Ibuilt the stabiliser, I could not see a way to glue the horn/ply hinge assembly after the sheeting due to the shape being tapered towards the TE. I am not worried too much about it as I haven't even decided if I am going to use it for driving the elevators the way you designed it, or if I will be using servos mounted at the back of the fuselage as done on sport aerobatic aeroplanes. It is all probably depends in how easy the CFrod will line up with the hole on the landing gear former F5B and how easy it will be to re assemble the c-pin into the hole while attached to the stabiliser.

As to making sure the stabiliser is square, I have used reference points in the fuselage and am confident that I will be able to align everything properly. As the wing was not built at the time, Icould not use it and Idid want to get some some progress.

Eran