If your goal is to have triangulated four-link that doesn't need a trac-bar, you should take a good look under coil-sprung GM cars....... A difference that I notice is that while your upper bars angle inward to the differential (as they should), you lower bars also angle inward from the chassis to the axle tubes. I think the lowers should mount more inboard on the frame and angle outward toward the ends of the axle tubes.