There are a lot of bowlers who think they can layout and even drill their own equipment. I give the guy credit for coming up with this idea. Guess, if you are happy with label drills, give it a try. on most balls, the cg will fall within 1 inch of the marked cg on the ball. But what if you want to drill somthing with the cg kicked out ? You will need a scale to insure you bring the ball back to legal specifications.
Good idea, but I think it will fail.