Tried and true wing retention method, same as I used on Byron Hellcat. I really didn't want to put holes through the carbon fiber tubes. The block resting on the wing is for the left wing. The block contains a 1/4-20 retainer nut. There's an identical block in the right wing, shown with a nylon bolt clamping the outer panel to the inner panel. I plan to use nylon socket head bolts - should be easier to tighten with an Allen-key vs. standard screw driver.