Not sure if any of the kits has a main wing tube as I had a bad experience with my Bud Nosen Cub which didnt and relied on the struts too keep the wings in place. When one strut failed the wing folded. Took me a while to rebuild the Cub from the rear of the cabin all the way up front. Now I have an aluminum tube going through.

Good luck in your decision.

Rafeek