Never had to use any spring compressor when the weight of the engine is still on the frame.
Floor jack and pry bar is all I use, put the floor jack under the lower arm once you have the spring lined up on the top pocket pry the spring through the coils to seat it in the lower pocket.
The key is to have the jack placed far enough on the outside of the arm so there is enough leverage to put the ball joint stud back thru the spindle.