deezler, if you go to our blog, you'll find a post outlining the difference between the "standard" and the "super" Heavy Hitches. I'd recommend the Super Heavy Hitch for your application because it has a greater wall thickness on the lower 3" X 3" tube. I've had people mount winches to the receiver and use them for skidding trees so you should have no problem at all!
As for the weights, Home Depot and Lowe's carry weights that will work and also JD dealers. Any 42-45# MTD, Arnold, Cub Cadet, John Deere suitcase weight should work.