Yes, its pretty tough to install springs on a frame without body weight but, it can be done with the right tools. You'll need to compress the springs fully (as possible) have a floor jack under the lower control arm (just touching) to keep the arm from going down to quickly once you release the spring from the compressor tool. This should allow you to put the spring in place, remove the tool and safety stuff, while the jack will keep it from expanding to quickly....you can slowly lower the lower control arm until you are at max spring expansion. If the frame keeps lifting...call a few big boys in to sit on the frame...body weighs approximately 500 lbs. So, 2 or 3 friends should do it.
Hope this helps.