The need for a WDH seems to get blanket application even when not needed. They are used to restore weight to the steer axle of the truck. Not sure sbout Ford but my stock hitch was rated for 1000 lbs load bearing or 1500 with WDH. 1000 lbs on the back just gets it on to the factory overload springs and levels the truck. This is what the truck was designed for and why the rear sits higher than the front in the first place.
The hitch is not so far behind the axle that it can lift the weight of the drivetrain and cab and passengers off the steer axle with 1000 lbs of tounge weight. The issue comes when your tounge weight is high enough to sag the rear of the truck, ie. a half ton or a truck that starts level. Regardless of load on the hitch, lowering the rear of the truck will transfer the trucks own weight rearward. This is when you really start getting weight off the steer axle.
If my truck weighs 6800 lbs roughly 3800 lbs of that is on the front axle when unloaded, more with passengers. I would not begin to worry about steering until that number got much lower. A simple free body diagram will tell you that with no sag adding 1000 lbs to the hitch will result in maybe a reduction of 250 lbs at the steer axle. Assuming hitch is about three feet behind axle and the steer axle is about 13 feet in front of rear axle. That is not much weight difference on the steer axle of a 6800 lb truck.
I have about 800 lbs of tounge weight and set up my WDH to restore the front of the truck to the unloaded position using 1000 lb round bars. Towed the trailer about 5000 miles. Then took them off and towed about 400 miles so far. At this point I cannot notice any difference without them other than a smoother ride since the weight is on the truck axle which has shock absorbers rather than on the bouncy spring bars.
Passing trucks feel the same with or without and I do stay below 65 mph with my ST tires.