Depending on how the sail is cut (flat or round);
the inboard, vs. outboad position of the track;
the apparent wind angle; and,
the relative speed of the wind.

Without dealing with the twist of the sail (which is a different issue) or the interaction with the main -- the optimum sheeting position might move forward or aft another 6-9", depending.

That can be a huge difference in the median point.

I think D'Arcy's post works best for a close hauled, inboard-ish sheeting angle. I think you'll find that an outboard angle would be farther forward by a considerable amount when reaching.

(On our 100% working jib, the close reaching sheeting angle for a block on the rail would about 1' farther forward than the inboard track. On a broad reach, it might be 2' forward of where the optimum sheeting angle would on an inboard track for a closehauled, windy day. We have a relatively small foretriangle and a jib which is cut low -- but not a deck-sweeper. )