The big problem I have with these plots is inaccuracy of my paddlewheel sensor. Even with careful tuning it is hard to get mine within about 5% accuracy. Water speed is one of the few hard data points that the computer uses to calculate true wind angle from measured apparent wind angle, and errors can be magnified. Add to that tidal variance around islands and you get a situation where apparent wind angle and sail shape feels more reliable than derived numbers. In a situation where the boat is being pushed sideways by current, you realize that the frame of reference for these calculation is the moving body of water rather than land. There is good and bad to that.

This does not make sense to me, on windfoiling the maximum speed you get when you are going 45-90 deg, but the maximum power you get when starting at 120-160. That's why wind-foiling in low conditions people start at 130 degrees and after getting the maximum of this speed, they turn to go upwind eg 90-45 degrees.