Just doing the same today. 10K lb. rated Curt 2" ball with 1-1/4" shank. Calls for 450 Ft. Lbs, so I loaded it with a 350 Lb. tongue weight and my petite wife at 100 lbs. Did not need to use a socket to hold the bolt, as the lock washer held it from turning much.
Center of the ball to the contact point on the tongue coupler is 12 inches. Pipe wrench is on the flats of the ball base, not the ball - lest anyone think me a Redneck.