You've got to try it for yourself to see if it works for you. Any weight added above 4cm up the handle will add swingweight. The further up, the more swingweight per gram.
But swingweight is only part of the equation, which is why it will work best if you try a few iterations of lead tape until you find what feels best to you.
For example, I am trying to customize one racket to match another. To make the weight, balance, and swingweight as close as possible, I added 7g of lead to 12:00, the very tip of the racket. But when I went to hit with it, it didn't feel right. On court, I removed 3.5g and it felt better, but I still feel like I should move that weight more to 10:00 and 2:00 or 3:00 and 9:00. So even though the math says it should feel the closest to the other racket one way, it feels better another way.
I do also recommend swinging a hammer as a training/strengthening tool.