Go to your local tire shop and get some stick on wheel weights, they have a tape on the back of them. Stick them on your stock until you reach the weight that works for you. By doing it this way you have the option of removing them and putting them on the stock in different places until you reach the weight and balance that works for you.
After determining where and how much weight you want then you can hollow out the interior of the stock and install the appropriate amount of weight.
