This one works better for me, I found it somewhere on this forum:

In the previous setup, the sheet tension increases/ decreases progressively from on side to the other as you ease/pull. You can see something similar with the speed of each section of the line. On the setup suggested here, things are more even (or better "centered"). On light winds and if you have some friction on your system, you might notice this setup running much smoother.

(edited: the "inversely proportional" part was not true...)