DelRay

Saul, I checked and I for some reason don't have any pics of the initial build of the wing, at least I can't find them at this time. I hope these shots will answer some of your questions, they give the general idea of the method I used to attach the wing tips and secure them in place for flight. The receiver tubes in the center section are aluminum tubing, i.d..400, I don't recall where I got them, it might have been from an antenna I built and had some pieces left over. You should be able to find tubing to suit your needs for this, I just used what I had on hand. The female tubes go through four wing ribs, and are secured generously with slow epoxy. The male pieces in the wing tips I machined from stainless steel tubing for a little more sturdiness, maybe a little overkill, but I know they won't bend. I built the entire nacell and then cut my hatch covers in them, giving me access into the tank area, and as you can see, a way to get into the securing pins for the wing tips. The yellow arrow indicates the locking pin hole for the front pin.
The wood stands I made from some wood dowels and plywood, they really make storage of the center section nice in the shop, and make assembly at the field a "one man" task, letting me get the main gear down and the nose gear unlocked and down easily before assembling the fuselage to the wing. I can cycle the gear, make pressure checks, etc. while on the stands. I hope these pics help you some. If I were to do it again, I would probably use a single, larger diameter male/female tube combination with locating pins to align the wing pieces. I added the pic of the strobe light in the nose of the wing tank, maybe something you might want to do when you get to that part of your project.
Jim