Late to the party here, but I just found this thread. I'm running a COT wing as well. Pooface and I have had a few conversations via PM on another forum, but have come up with some pretty similar solutions to mounting. Here's mine, made at home with hand tools.
I put rivnuts inside the trunk lip so it's easy to R&R. I left the mounts solid to cut down on drag. The tethers are really easy to remove, they just pull out when you remove the anchor. Interestingly, they actually cross inside the wing so the left anchor is attached to the right end plate.
I've had a chance to do one track test with it. Our local track usually has a peak speed of just over 70 mph with an average of 50, so it's not a high speed track. Still, that peak speed takes place on a long sweeper and I'm very much limited by grip instead of power. Short version: 2 seconds per lap and a gain of nearly 5 mph in the sweeper. A very definite change from oversteer to understeer in the sweeper, even with a 3" splitter.
Since the angle is adjusted by moving the front mounting bolt to different holes, it's completely repeatable. So I've just been monitoring the holes used, as it's a lot quicker and easier than ensuring I'm on a level surface and measuring with a level. IIRC, each hole is good for about 1/4 degree, so if I change the rake of the car I can just offset my notes about holes by the same amount. With a 1 degree nose-down change, I'd just change from hole B2 to B3 for the same wing angle.
If there's interest out there, I could probably get Mark at Paco Motorsports to duplicate these. Even better, I could get him to angle the bent section differently so you can open a normal trunk at least partway.