It could be bracketed with a 1/4-ball and a 3/4-ball aim, but overall I think it's easier to visualize 3 parallel lines. To me, using the angled (blue) line between ball centers helps to locate the centerline, but it makes more sense to move the end of the blue line to the right edge of the cueball, to make it parallel to the other lines--even considering the 3D view causing the lines to converge (towards a vanishing point). I know this is still all the same equal-distance/double-the-distance aiming, but is there an advantage that I don't see, with using the center-to-center line, angling *across* the midline (red)?