I would suggest going to the next glider field and checking out how the wings are secured there, after all they are built to be taken apart easily (folding the wings, often at several points along the wingspan), also to carry the loads once everything is back in place. And they have design at least +5.3g/-2.65g in normal operation (yes, every glider is according to EASA at least an utility category plane). From my experience, and that is a bit out of date, it is usually one or two bolts for the central point, and quite small pins for mid to outer span points.