Go with the Sig kit. Build a jig to fabricate the wing 'carry thru' for wing spars, i.e., two piece wing with functional struts. The carry thru tubes have all neccessary music wire to resemble fullscale 'greenhouse'. The carry thru will be brass tubes that fit the music wire stubs inlet into wing spars. A grub screw will fit into a hardwood block near wing root underside and the grub screw will snug into a groove in wing wire stub... or you can have a nylon screw thread into wing root from inside fuse. The loads on this are minimal but this will keep wings from slipping