RE: Double truss control horns
Looks like a plan to me.
Photo shows a 2024-T3 double truss horn embedded in the 5/8" ash half-round L/E on the aileron of my 33% Extra 230, during construction.
Robart hinge pins are recessed into the L/E at the radius, just like the prototype. I'd have to rip that aileron apart for those horns to fail. APITA to build, but about the strongest horns I could come up with.