With a tight rack and a center hit, both of them go towards the side naturally, but they usually hit too low. Cutting a bit (not a lot) helps send one ball a bit higher and the other a bit lower. Sometimes the other doesn't seem to move as much or as fast. Usually just cutting doesn't get a ball in the side for me.
To really alter it you need draw. I guess the theory is that draw puts topspin on the 1 ball, which puts backspin on the balls behind it, and those balls backspin off the 3rd row... bringing them high enough to go into the side. Only a tiny bit of the spin is transferred but it's enough to drag those balls up a few inches.
I think the fullness of hit on the 1 matters a lot too in how much transfers, which is why the draw thing works best when you don't cut too much.
To really alter it you need draw. I guess the theory is that draw puts topspin on the 1 ball, which puts backspin on the balls behind it, and those balls backspin off the 3rd row... bringing them high enough to go into the side. Only a tiny bit of the spin is transferred but it's enough to drag those balls up a few inches.
I think the fullness of hit on the 1 matters a lot too in how much transfers, which is why the draw thing works best when you don't cut too much.