Interesting. I will add some charting to my program.

I identify when the tack has begun (combination of drop in average speed and/or change in lat/long) to when the tack "ends" (increase in average speed). Two of my metrics are time to reduce speed or decelerate and time to accelerate.

Given your input, I think I will add distance covered on tack as well. Maybe I can work the math to show angle or arc of the tack as well.

Given comments on this board, I have begun doing more wide tacks. This increases deceleration time, but reduces acceleration time.