I'm being lazy n not reading back thru thread, but assume you have adjusted the 4 bolts that hold rear hinge to door to maximum gain.? Plus checked hinge for wear.? The Malcom engineering rebuilt units might be an option if you think there is play in the hinge and you have eliminated all other factors. Related to smooth running rather than height but check waistline track for sharp edges caused by roller. Gently file as necessary.