5.9 Magnum flywheel - DIY with bolt-on weight??

I used the method in the link above to draw a parallelogram with 3 vectors, one for each hole in the flywheel. I set the center vector at 100 mm. The two other vectors came out to 63 mm and 64 mm so I used .635. Here's the calculation.

Total weight = 4.65 oz. 4.65/3 = 1.55 oz per hole.
The distance from flywheel to center is 3.84"

(1 x 1.55) + 2(.635 x 1.55) = 3.52 oz at the center vector

3.52 oz x 3.84" = 13.5 in oz

Feel free to critique the method.

Note that its quite close to the value successfully used by 340 Duster (2.28 oz x 5.625" = 12.825 in oz)