Well depends on what you got hanging off the back. Personally I believe in sharing the load across the whole tractor and not just the one axle. If you are going to be putting an implement on the rear, I would add enough weight where you don't see a noticeable shift in weight when you raise the rear implement. Also the type of rear implement can make a difference in the amount of weight. Box blades dig in and want to pull the front up, so more weight in the front will help to keep steering on the front wheels.
And honestly a lot depends on the terrain and how you would be traversing it as well, steep hills going up them forwards with heavy weight on the rear, you might want more weight. Flat ground, not needed so much.
Light steering is almost never a good thing, there is nothing like going straight when you need to turn (for some reason trees just don't get out of the way, LOL).