I like to put the cue ball three ball widths from the rail, against the 3rd diamond. Aim for just less than a 1/2 ball hit on the stacking ball with a 1/2 tip top and a 1/2 tip left. Medium speed is all you really need. If the cue stick gets pushed too far, aim a little thicker or hit is a little slower. You can also adjust the initial starting point of the cue.