My friend suggested something today that I ended up doing.
Used 1/2x6" eye hooks, all-thread and fender washers to hold it down on all corners! I can tighten it down and remove it with a 3/4" wrench, and in the video below you can barely see the studs sticking up. Will try to get a picture when I take it off for painting.
Tuft testting with my GoPro!
I think the cab is throwing up some huge longitudinal vortices which are holding the tufts down. I don't know if there is any good way to stop these except building an entire aero topper. Either way, this tonneau should give me a bit of a mileage boost, and for about $26 in new materials, the ROI should be short.