Reading this thread, the OP clearly is overloading the front axle and will destroy it if he continues to use too little
ballast. He should read the owner's manual to see their ballast recommendations and follow it. I suspect it will call for a lot more 3 point ballast than a 400 pound box blade even with 75% fill in the tires. The OP probably will have to fill the tires to 75% with something, either topping up the methanol/water or replacing it with beet juice and then adding wheel weights and/or having a lot more weight on the 3 point hitch. He could either get a much heavier box blade, add extra weight (iron, solid concrete blocks, etc.) or some combination of the two. Without knowing the exact ballast recommendations, it will be hard to say exactly what he should do.
The discussion about 40% liquid fills relates to radial tires on row crop tractors where ride quality while roading >20 MPH and power hop are major concerns. Those are not going to be concerns with a tractor that has a top speed of less than 16 MPH and the main concern here is using a loader instead of a giant no-till drill or ripper or some other high draft load pulled at high speed.
I also live in the general region the OP does and bought my tractor here. My rear tires came filled to 75% with water/methanol and this is essentially standard for any ag tractor. It used to be calcium chloride and water but that has been moved away from due to the corrosiveness of the calcium chloride. The commentary about beet juice locally is that it's a pain in the behind as it makes servicing tires extremely difficult due to the sticky mess it creates, and it's expensive stuff, so few ag tractors run it. There is little row cropping done here, cattle ranching is the main agricultural pursuit, so ballasting tractors properly for handling large round and square bales is much more important here than mitigating power hop. Shoot, power hop isn't even possible on many tractors here as that only occurs with driven front wheels. You don't need MFWD to run hay equipment or feed bales, so there are a lot of 2WD tractors around here.