That's the point I was trying to make, Jerry. There are two different adjustments.

(1) Shock length at ride height: Just compressing or loosing the spring with the adjuster collar can cause a lot of problems. To adjust coil-overs, you need to know total travel. Measure the eye-to-eye length with the car elevated and the rear axle hanging on the shocks. Then you need to know the full collapsed length of the shocks, which is a little harder to determine if you don't have the spec sheet. The sure-fire method is to take one shock off, remove the spring and fully compress it. The ride height of the car should be near the midpoint of shock travel - give or take a bit.

(2) Ride stiffness: That's what the adjuster knob is for. Your description covers it perfectly.