RE: hard points in a composite wing
I just drill a hole in the the bottom of the wing, insert the same sized dowel, usually at least 3/8 if not more, and glue it in with Gorilla glue. Then when the glue dries I trim the dowel flush with the surface, drill a hole for a bolt and then tap the hole with 4-40 and soak the threads in thin CA. Works good, I used this method the 339 ordinance, very solid.