With the highest point of the radius above the contact point of the grip, the radius tends to lessen the effect of bow movement at the moment of release. The same idea applies to the side of the sight window. A small point of contact on the side of the arrow in the sight window, again just above the contact point of the grip, would tend to lessen the effects of torque.
I have set up bows with flat shelves and with radiused shelves, and I find the slight radius to be helpful. I hope this helps.
Joe