control rig backwards solve

Hi. I've had amazing luck with daz imported characters using a modified twisted bytes control rig for forward solve. I am having real serious issues with the backwards solve. Has anyone had any success? My pelvis is feet off the ground, and my chest is in the middle of my head. I am suspicious the hip to pelvis bone difference between the daz and epic skeleton is the issue (and maybe the collar bones,) but am lost beyond that.