Brief Description: Horizontal Stabiliser - Hinge Brackets
Cleco the HS-412PP and HS-413PP elevator hinge brackets to the rear spar assembly and run a #30 drill through all the holes.
Cleco the HS-411 assembly back to the spar. Drill/enlarge the bolt holes that will attach the HS-411 assembly to the spar to #12.
Mark all the parts in the rear spar assembly so they can be returned to their previous positions. Use a "Sharpie" pen or equivalent for all marks on aluminum, but in this case the ink will be lost if you clean the parts for priming.