I have done it one side at a time, but it scares me. The car is teetering on two corners if you already have stands under the rear. If you have the rear on the ground and jack one side up and put it on a jackstand, it sits at an angle. Then when you start the other side it puts side loads on the first jackstand. I like the car to go up evenly on both sides and come down on jackstands level. I believe that is the best way to have the car stable w/o any side load on the jackstand.