I can still lift the rear tires off the ground on a TYM T503 cab with a 1100lb flail mower on the back. Ended up using the counter weight off a small forklift ($250)and attached lifting pins to it to use on the 3pt, tractor is extremely stable. With so much weight, I don't use it often, but when I do I'll take my time and try to operate smoothly.
800# in the form of a ballast box is light enough that you can still lift the rear tires.
Which puts more weight and stress on the front axle than if you had no ballast box.
So those of you with excessive weight on the rear of your tractors.... How do you get the FEL to dig anything? I had 1000 lbs on my three point. You couldn't dig anything. A 1" stone in the dirt was enough to lift the blade of the bucket. I removed 400 lbs and what an improvement in FEL performance.
Yes the rear of my tractor is light at times but I can just reduce the amount of dirt or gravel in the bucket.