KJ, Z:

In a situation such as this, it may be necessary to resort to diagonal jacking of the chassis to cause enough weight to be transferred to the front corner.
Try placing a jackstand, set as low as possible while still getting it outboard as far as possible (tire clearance gets involved here), under the control arm. The farther out the stand can be set, the better.
Then jack under the diagonally opposite corner of the chassis (not under the suspension).
A greater percentage of the car's weight will be transferred to the front corner, and if all goes well, the spring will be compressed further than by jacking only the front corner.