reading other build logs it seemed easier to rivet the 1220 control horns to the rib first and thenm rivet it the AST skin. I copied the method of fixating the rivet squeezer in the vice from another builder. Also using the plastic tube piece to keep the 2 pieces together (see image 2) while the rivet is squeezed. Also something I learned from another builder.
Using my rivet gauges I verified the correct head size.
