I build control hons from 3 layers of 1/32 aircraft ply glued with med CA so I have 9 plys. I have tested these very harshly and have not had a failure. I glue them into a full depth slot in balsa the thickness of the surface, after boring 2 or three 1/16 holes for clevises or cables. Rudder horns are one piece that go completely thru the rudder and glued with epoxy. I had a plastic horn on a wire elevator joiner break on the first flight, luckily on the first landing. Sorry about the double entry, I don't know how to erase it.