I would be surprised if its not mentioned in your manual and also listed in the FEL manual. Usually it should have a suggested amount that might also include
ballast in the tires. In my case Deere has a suggested break down that includes ballast in the tires. But the 3pt suggestion is a at least up to 900lbs alone (portland cement - a little less if not portland) and added together (ballast and/or 3pt weight )should add up to at least 1,100 lbs or more.
So for a machine that size I would be looking at least 1,100 lbs or more total that may or may not include rear tire ballast.
Again each is free to use whatever works for them - but at least refer to the manual as a guide
Duc