Highly recommend putting fluid in your rear tires if you haven't already done so. That will add a couple hundred lbs. Your 3 pt will lift about 600 lbs at 24" behind the lift arms, but most implements used on a BX are lighter than that. I've found a 400 lb. box blade works well as counter weight and it's a useful implement as well. That's probably a good weight for a ballast on the 3 pt... maybe more if you don't do the tires.