For a long range rifle that will be primarily fired from a prone position using a bipod you want about 2-3 pounds of downward force on the rear bag ( I would have to get out a couple of rifles and check the exact poundage). Exactly where the balance point is does not matter very much.
For a hunting rifle that is primarily fired from the shoulder you want the balance as close to the shoulder as possible to reduce the weight on the forward hand. Adding weight to a off hand hunting may change the rotational tendencies.
Here are a couple of photos of adding 2# of weight to a stock to get more downward force on the rear bag. End weight of the rifle is 18#.