[Wavery]

There is absolutely no upside to backing up a steep hill with the WDH bars on.

The forces when backing while the trailer and TV are at extreme angles changes everything. The spring bars are no longer just spring bars. The force is no longer just vertical, it is also horizontal (due to the upward angle of the trailer in relationship to the hitch). The spring bars are actually trying to lift the rear wheels of the TV off of the ground while at the same time, trying to assist in pushing the vehicle up the hill. With a 750# WDH, I'm a little surprised that this activity didn't bend the spring bars. That's why I thought it might be a much higher rated WDH......

The WDH is designed to transfer weight to the front wheels of the TV while towing down the highway to improve braking and steering. They are not designed for backing up a sharp incline like that and are no longer needed. However, due to the lower bumper from the addition weight on the rear axle, the OP may need to install Air-lifts for the additional rear bumper height.

In fact, I think that the OP would find it easier to push the trailer up that grade w/o the WDH. The lack of weight on the front wheels is not an issue and the 500# of tongue weight is not going to hurt the hitch or TV in any way. In fact, some people put a receiver on the front of the TV (with just a draw bar) for just these types of scenarios. My SIL does that with his 35' travel trailer (800# tongue wt) and just has a class III hitch on the front of his truck.