Torsion bar adjust for rear

[anlauto]

You should also loosen the large nut on the lower control arm pivot, otherwise you're just putting all the stress on the bushing when adjusting the torsion bar

[73TopBanana]

your 2 cents is great 

[YellowThumper]

As has already been noted, you can adjust the rear utilizing the T bar. As most of the weight load is in the front. Minuscule unnoticed movements in front will leverage to larger movements in the rear.
Yes X2, 3, 4... unload the front when cranking the adjuster. Then drive to have it settle properly before recheck. Be sure your shocks front and rear are not the pressurized type. I have seen these cause issue when one side pressure fails and the other does not.
Also be sure to measure heights from key points like frame and not just a wheel well opening height. These are notorious for being off from side to side. Make sure all tires have same air pressures left and right. If at end of day you suspect the rear springs are bad. Lift front, remove tires and set car down on front rails. As far forward as you can. Obviously making sure front is level side to side. This places all the load on rear wheels. Now measure the heights in rear to confirm.