Anthony;
My control horn setup is simply an 1/8" solid carbon rod carefully glued into the aileron near the LE. In some rare cases I have had to angle the rod so that the nylon connector and clevis pivot will end up directly over the hinge line. In my own builds I have hardpoints built in that extend from the LE back toward the TE of the aileron so that the load applied by the carbon rod will be distributed properly. I could tell that in these ailerons the whole area behind the servo pocket was solid...likely the typical internal construction of stacking several little ribs against one another in this area.

I drill a hole using a simple jig and a long 1/8" bit (gives me more sight line to simply keep the drill straight). I use a piece of tape on the bit as drill depth gauge. A dry fit check and then I use thick CA in the hole and insert the carbon rod cut to a length that is about 1-1/4" above the hinge line. I can adjust the exact height of the nylon piece later, making sure all 4 will be the same and at a height that will give me the throw I want. I simply thin CA the nylon to the carbon and the job is done. This is an old method handed down to me years ago by Ron Barr. In my opinion it simply is the lightest, strongest setup and I just got into a habit of using it year after year. I found that with a soldering iron I can replace the nylon pieces rather easily if needed...which I needed to do almost every Winter, back in my glow days.