If you only need it one time, why not rent it from one of the members?

Or, if you have a good floor jack and good jack stands, you can do without.
Get the car high enough to allow the control arm to fully lower. Then put the floor jack in place and remove the hardware that holds the arm. Then slowly lower the arm till no tension is left. Worked good for me on my W124.

By the time the arm is fully lowered there is not much tension left. Easily controlled with the floor jack the rest of the way.