The upper, Do you mean the Axles? There is no upper suspension arms. Changing the axle length would not effect caster only camber.
Yes the forward torque arms are pretty heavy duty and are a solid to frame mount (bushing isolated at Diff mount ) but is also adjustable in order to have correct pinion angle (expected with bushings a 3* flex) these arms are long and set to account for upward torque roll as well as the upper mount. That mount I decided was better off copying jags fore and aft setup unlike the hot rodders of the 80-90's side to side style mount. This also helps with the side to side motion. Now I still have a few more bits I have to build to finish this. I have to get the lowers mocked up so I can build the lower strut arms, rear rods??, and coil over mounts. All will effect the limit in which the rear end will move under load.