I've been holding the wings of my H9 Extra together with VELCRO.
The opening in the wing is so large that I epoxied a 1/2 inch plywood piece in there, vertically behind the root rib.
I then make a loop between the 2 wings with a long 1/2 inch velcro ribbon, with the overlap being slightly smaller than the fuse width. To add extra tension, I then pinch the velcro loop close to each wing with another small velcro loop (that is also used to capture the servo wires and hold them together).
I've been using this technique for over 2 years now, never a problem, light, reliable and strong enough.
Ben