I like to balance the loader capacity with the rear ballast. My lx4900 lifts 2500, I have rear tires loaded which adds 1100, and have a 1500 lb box blade. Loading the rear tires really helps, and is always there.
I have loaded tires and I hook up my box blade when I so loader work. It is only a 4' blade and weighs about 250 pounds. It works good unless I have a full bucket of dirt and have to go down hill. The rear tires get a little lite for my taste. I have also strapped 4 cement blocks on my blade and it makes it much safer. So with loaded tires I would say at least 400# and you should be good.