Actually I was thinking 4-40 metal
screws. It helps to read what I'm thinking, not what I type.
Yeah, 4-40 nylon would definitely be too small. You think 10-32 nylon bolts might save the wing during an impact? Runner bands are out, 10-32 nylon bolts is an option, but I think I'm still leaning toward 4-40 metal screws.
The center section structure at the trailing edge might need some modification to support whichever method of attachment we decide too. The heads of small metal screws would rip through 1/16" balsa. Definitely would at least need some hardwood reinforcement there. Or, at minimum, fairly large diameter washers under the screw heads to distribute the pressure over more surface area. Maybe, I could cut some washers from 1/16" ply. Thoughts?