Ballistically (once the arrow leaves the bow), the less time gravity and wind have to act upon the arrow the better. A 400 grain arrow @ 260fps will drift and drop more than the same arrow @ 300fps.

Gravity is constant. What combo of arrow weight/speed that would yield the least drift over a particular distance I have no idea- a lighter arrow sheds velocity faster rate so at some range, will be more influenced by drift than the heavier/slower arrow.

As for the accurate bow, accuracy is only another name for consistancy. So mechanically, shot to shot consistant velocity and harmonics should deliver the same arrow to the same spot time after time.

What screws it up is that bows are held by humans and we are variable.

just my thoughts