For beginners:
Assuming that the center of the cue tip is aimed at the center of the CB, then sighting down the side/edge of the shaft would be 1/2 the diameter of the tip to the side of the center of the CB.
If the tip has a diameter of 1/2 inch, then the shaft side would be 1/4 inch to the side of the center. This is a constant so it would only work perfectly for one cut angle only - where the contact point on the OB is 1/4 inch to the side of the center of the OB. This would send the CB 1/4 inch to the outside of the CP on the OB and is one of the cut angles that abides by the double distance aiming method/system.
You need less than 1/2 tip for thicker cut angles and more than 1/2 tip for thinner cut angles.
Aim the side of the shaft at the center of the OB and see what cut angle it achieves. So you obviously wouldn't use the side of the shaft for a straight in shot - use the center.
If you can imagine or visualize the contact point on the OB, then use the double distance method/system unless the CB and OB are very close together.