What is ballpark figure for the amount the rear springs should compress from unloaded to loaded?

(SVA rear axle 282 kg).
2 inches sound about right?

So spring rate of 150 lb ins?

<<-- this is unsprung weight so sprung weight that is acting on the spring is about 200 kg; i.e. less axle, wheels, brakes,tyres) - should I be looking at even softer springs? 150 seems a bit low...


[Edited on 5/8/08 by 02GF74]

My live axle car has 150lb rear springs.

Total weight was 565kg at SVA.