The wing to saddle fit must be a good fit to start with, if the wing is mounted to where you have to really tighten the heck on the hold down bolts just to get the gap to close up then a great deal of stress is where the wing meets the saddle . This can really stress the wing in that area...it seems to me that most of the failure happen just out past where the wing meets the saddle. So if you bolt the wing on and see the fuse/monokote starting to start to wrinkle as the bolts are being tightened the some work needs to be done to make a better fit.
The reason I say this is because I saw first hand a GP Giles 202 ARF wing break just about .5in. past where the wing meets the saddle. The owner had to really tighten the heck on the bolts just to close up th gap anf the fuse was buckling bad in that area.
Just wanted to mention this as a heads up and not accusing anyone of anything.