Originally Posted by ChrisSlicks

You have to adjust the spring perch and the shock body. To adjust the shock body to have to remove the lower shock mount bolt so that the bottom of the shock can be turned (after loosening the locks).

Basically you need 2 jack stands and a floor jack so that you can support the back of the car and then use the floor jack to raise/lower the rear control arm.

Your spring adjuster looks like it almost maxed out.