The dual cam bars are square, and have the saddles that fit over the cams.
The 750 lb older bars with the old style cams would be about right.
Or, if you get a new Reese Straight line trunnion style hitch with shank and 800 lb weight distribution bars
Weight Distribution - Reese
and dual cam sway control
Weight Distribution - Reese
You should be hitched about right.
The lighter bars are designed for 3/4 ton pickup and use with stiffer suspensions because those suspensions don't need as much "help", and the 1200 lb bars are designed for tow vehicles with a lighter suspension than your pickup.
You don't want to be over hitched, OR underhitched.
The weight distribution bars should bend about 1 inch when engaged to the cams and the trailer sitting level hitched up. 1200 bars would simply be too stiff.