I ride a 2018 67" Connelly GT and last week put a CG fin on it. I'm a shallow / long guy, and the numbers we settled on are 2.439" x 7.027" x 0.767" w/ 7 degrees of wing. Skiing 34 mph.
A few things I've noticed:
1) I haven't found settings that absolutely don't work. No matter what, the ski ran buoys.
2) You can use more extreme numbers and ratios on the fin to push out more performance in whatever aspect you are looking to improve, without the usual large negative that comes with it.
3) It is far less sensitive than a standard fin. You can definitely be off by several thou in any direction, and not really notice much. I made a mistake with my clamp last weekend, and the fin moved around quite a bit during a tournament. But my scores remained the same for all 3 rounds.
Another cool thing I feel in my setup personally is that the tail washes and slides through the turns because it's shallow, but then behind the boat it feels deeper. Kinda wild.
With each set that I take on the fin, combined with the variety of settings we tested, I'm becoming more convinced it's the real deal. Let me know any questions.