Weight in the tires adds a LOT of stability. Actually better than weight on the 3pt, which can become unstable in the wrong off camber situation.
The unloading the front axle discussion gets extremely complex. I never consider weight added to the rear of the tractor as unloading the front axle. On the contrary. It actually allows the operator to put larger loads on the front axle.
Here's an example:
1. I'm trying to pick up a load with the FEL. Rather than pick up the load the tractor simply raises the rear wheels off the ground. This action applies XXXlbs of weight on the front axle.
2. So,,,,, I go back to the shed and attach a Ballast Box, rear blade, brush cutter, whatever, on the 3pt. Now I go back and try to pick up the load again using the FEL. This time the load is actually lifted off the ground and the rear tires remain on the ground. This action applies XXXlbs of weight on the front axle.
Which example above applies the most weight on the front axle?