How it's unloaded depends on type of suspension. If the spring acts on the lower control arm, like on most trucks, you would put support undder the control arm, preferrably under where the spring seat is. This puts the load so that it is supported at the spring, not the spindle/balljoint. If the spring acts on the upper or it is a strut vehicls (Fords/AMCs/ almost all modern front drivers), then you would support the weight on the frame, leaving the lower control arm free.
