How high are you jacking the rear of your truck up when you latch up? I'm a little confused by some of your comments about putting too much weight on the rear as the PURPOSE of any WD system is to REMOVE weight from the rear and switch it to the front axle and back to the trailer axle :H You should adjust the hitch so that when latched the spring bars are approximately parallel to the trailer tongue frame AND with enough weight transferred to REMOVE the excess weight from the rear which will, at the same time lower the front end by replacing the weight lost by pressing down on the rear. Usually that is accomplished by latching up about the middle of the chain.
Also consider that in order for everything to work correctly the spring bars ALSO need to be correctly sized for the trailer. Generally I recommend using 15% of the trailers GVWR (the heaviest the tongue will ever be) as the weight of the spring bars. Come as close to this weight as possible without being UNDER that weight.
Good luck / Skip