Roy,
I'm not a bow design expert, but yes, the purpose of having the arrow to bow contact at the "vertical axis" is to eliminate, or reduce, hand torque. That's the same reason for the 'deep' grip cutouts on recurves: to have the hand contact, the arrow contact, and the vertical axis all aligned.
I don't believe that this is possible with 'most' long bow designs I've seen, as the grip/riser seems to locate the hand behind the vertical axis of the bow.
A well designed LB will have both a slight convex curve to the arrow rest that aligns with a slight convex/rounded face plate, this helps to minimize the arrow contact with the shelf and face plate, and I would think that it would be as close to the vertical axis as possible.
I believe that the location of the hand behind the vertical axis on the LB is what makes them a tad more difficult to shoot relative to a well designed recurve. Uhhh....rather challenging for many of us, myself included! But Fun!