Jim, there is an even easier way, cut a slot about 1/2 in by 1/8 in at the trailing edge of the wing, cut a slot in line with the push rod ,without the clevis or balljoint,push the pushrod forward to shorten the slot.
This slot will be about 3/16 in by 1 1/2 in long.
Put the horn in the wing slot and slide it back to the rear of the slot at the trailing edge,then slide the wing into the fuse,align and glue.
The horn and its parts can now be slid forward and inserted into the rear of the wing and reinforced with a fiberglass wrap.
The fillets will cover the slots at the trailing edge and you only have the patch the slot for the push rod.