he has to know the sheeting angle and ave windspeed (luff sag) among other things.
A self tacking jib can have a tighter sheeting angle, which I think could aid in coming about. It could give more forward drive for a longer period as you turn into the wind, then can be sooner to catch the wind on the other side than a non-wrongsided conventional jib. I'm not talking about foils or pointing, but just how that graph implies a self tacking jib doesn't have to be inefficient. A tightly sheeted one may hurt tacking more than it helps though, in terms of reducing weather helm.
My Hobie i12s... sailboat in a suitcase! Look for it in THIS