The wing span is 87", built from Promark plans (Formerly Ohio R/C). For wing tube length, once everything is built and fit, I sand the wing tube to length to achieve a tight fit. Usually loose an inch or so. The problem is you just don't enough socket to match the tube, the tube and the socket are the same length. My 36" wing tubes end up 34" or less. I hope this answers your question.
In the last photo the skin is soaked with ammonia and placed back into shuck with the core, not forced, just enough to prebent the wood on the rear section where the bend is rather sharp. I usually allow this to dry for several hours before bagging.
Tite Bond II works well for gluing the skins together, it's water resistant. Elmers and regular Tite Bond are not, skins glued with non water resistant glue don't make it through the bending process as the glue joints fail.
I have sheeted wings without edge gluing the sheets together, just tape. The glue foams up under the marking tape onto the finished side, some joints were uneven. It worked OK, I just found that edge gluing works better for me.
Tony Hallo