The instructions have you finish off the bellcrank support. When riveting the fuselage skins, I preemptively riveted the bottom of the F-728A bellcrank channel to the bottom skin. Not entirely ideal, but I don't think this is too big an issue as it just makes riveting of the F-728B angle a bit more tricky.
So not that I am commented to my setup. I drilled the F-728A channel to the F-706 Bulkhead. Dimpled the holes for AN426AD4 rivets and then bucked the rivets.
