Lamar, I've just entered your figures into the equation, assuming your empty tongue weight of 580 pounds, 33 inch bars, and 206 inches (a guess) from trailer axle center to ball, and rear TV overhang of 60 inches. The chain tension required is 816 pounds, or 408 pounds per chain. That's about 20% less than my rig, because of your lower tongue weight I obtained from searching this forum. I use an Eaz-lift 1000lb hitch!
Nick.