I also found that it flexes/compresses, enough that the trunk lid rubs on the top of the taillight.
I recorded this image at ~80mph, zero-ish AOA.
While I didn't rigidly mount as you're discussing, I did make some stand-offs to stabilize it.
I remember seeing pictures of someone on here has their wing mounted to the hinge mounting points. A good solution if you're willing to cut and pin your trunk lid.