If you want to employ a pendulum stroke, then you should place the ball about 6 inches away from your toes in your putting stance. Usually when you do this, a 75 degree head lie angle is ideal. But there is always a reasonable allowance one way or the other. Have someone take a picure of you in your stance and compare it to the above graphic. If your stance is more upright, then order a 77 degree Head Lie Angle; or more flat, then order a 73 degree angle. But head Lie Angle is related to Shaft Length so before you decide on final Head Lie Angle, take a moment to consider Shaft Length. before ordering your new Quantum Golf Putter.
Go to the dowel rod department of your local hardware store. Pull out a 36” long dowel rod of each of the following diameters: 7/8", 8/8", and 9/8", Then in turn hold each as you would your putter. One will feel better than the other two - that is the Grip Size you should specify when ordering your new Quantum Golf Putter.
While you are at the hardware store using a dowel rod to determine grip size, now would be a good time to also consider Shaft Length. Here is how. Use the most comfortable dowel rod as a pretend putter. Stroke it to and fro and also vary your grasp sometimes higher and sometimes lower; also vary your stance, sometimes farther away and sometimes closer to your imaginary ball placement. Continue until you find the grasp and stance that gives you the most smooth and sure stroke. After that, make a light pencil mark on the dowel rod where the heel of your upper hand grasps the dowel rod, and then add an inch to that length to get the putter length you should specify when ordering your new Quantum Golf Putter.