I meant sailing to the visible wind, as they do on real yachts. Recalculation of the visible wind in the true wind will always give an error at small angles of attack.
When driving in tacking the sails chosen are tight. The steering is controlled to maintain the course as close to the tacking angle as possible without significant loss of speed (heuristic rule 1: sharp course is more important than speed).
But, when the speed drops, the drift increases and the actual path of the boat becomes noticeably larger than the angle of tacking, and it will not be noticeable on the weather vane! The influence of this factor is amplified when the wind gets stronger. In addition, with further strengthening of the wind, the roll increases, hence the effective area of the sails decreases and the drift increases even more
If it is impossible to visually determine that the sails are winded and lost traction, the most important indicator of this is the Roll. Given the above, the Roll should be within certain limits for a certain wind force.