More info...I measured from the mast rail to the center of the traveler and it's ~72". From the mast rail to the 1st of three boom tangs is ~82.5". The three tangs are spread about 4" apart. Please refer to my pictures below.
Referencing the
assembly manual, figure 54 on page 19 shows the bitter end of the main sheet fastened at the center tang. The parts location illustration on page 25 shows two tangs with the bitter end fastened to the rear block. I understand these references are meant as guides. I also noted that my block arrangement and the two previous all pull the boom at an angle from the vertical. I think the horizontal component of this force contributes to inadvertent and undesired rotation of the mast as the boom gets pushed forward. If I mounted another tang on the boom so as to bring the block group over the traveler's center (where most of the time is spent anyway) I think that this horizontal force would be minimized or canceled. This should allow the mast to fully conform to the airfoil shape directed by the apparent wind's entry angle.
Another point is that when the traveler is fully outboard from center, the distance from the mast rail would be longer putting the blocks directly over the traveler.
I suppose experimentation is in order.
I would appreciate any comments you care to render.
Eric