I think your total weight is more important than the ballance for a lot of reasons. If you carry 12 front and 8 pounds back, or vise versa who cares. If you carry 120 front and 80 back, you might have too whatever you want to do in order to spread the weight. My front paniers are pretty small so I put all the heavy metal stuff in them, and it comes out at what it comes out at. In most cases front paniers and racks are not designed to carry really heavy loads. I am doing up some 4130 front racks that would allow me to carry the same size paniers front and back, and not have the risk of the front rack breaking, but a lot of people don't have that kind of option.