Since the boat was apart I thought a "wheel alignment" was in order as there was some elongation of the beam bolt holes. The holes have been filled with epoxy and redrilled working from the centreline of the beams and centreline of the hull beam trenches. The front beam and back beam are slightly different in length as are the width of the front and back beam trenches, but when you divide the length of the beams by 2 less the half trench width the measurement is the same for both beams, which is a centreline through the beams from bow to stern. If your hulls are symmetrical you can measure "in to out" as a double check to see if your hulls are parallel, mine measure 1795 which is a centreline to centreline measurement for this boat.
Cheers,
Roy 1770 Rebel Without a Clew