1.25 inch P clamp with a rivnut mounted in it. You can see them in my autocross youtube videos.
That second element does move around a bit. At least one support, maybe two, added would get rid of the flopping around.The only reason this one isn’t going in the trash is because I’m considering putting it on my lawnmower. All aluminum from Amazon. I think it was like 200 bucks. Looks fine but the upper foil wiggles in the wind like crazy. I just ordered an ICBeamer on Amazon. Mounting holes are about 6 inches off but I’ll just fab a plate to adapt.
That's a good looking wing!! Love the adjust-ability...Has anybody tried Racebred yet? They have an aluminum wing in a variety of widths, 68" is $735.00 including endplates. You specify bracket spacing when ordering. They claim to have them in stock with shipping 1-2 weeks from order for raw aluminum, or 3-4 weeks for powder coating.
Here's what I'm thinking of: https://racebredcomponents.com/products/250rs-aluminum-gt-wing-airfoil?variant=39273252192391