russell
You don't have to be an old guy like me to remember when the majority of point-blank shooters owned a barrel vise, action wrench, removable butt plate, and pre-determined weight. There was time alloted between LV and HV matches for shooters to add (or take out) the weight. Now-a-days, of course, that same majority simply fine tune a LV and shoot it in all three classes.
It seems that weight distribution, balance points, etc has gotten a lot more complicated since the Interent because I don't recall anyone really agonizing over those things back then. Of course, maybe we simply weren't smart enough to realize how dumb we were.
Your actual balance point can be determined very easily and it's also easy to determine the weight differential with just one scale. But, you'll probably find that the weight of the barrel will determine the weight distribution and you can't do much to change that. FBike's 65% - 35% is probably what you're going to end up with no matter how hard you try but that seems to work OK. With long-range guns with really heavy barrels you'll be happy to get 70% - 30%, but that seems to work too.
Bottom line, there are more important things to worry about.
JMHO
Ray