You want the springs to be compressed with some travel left, that puts your car at the ride height you want it at. You can get a short spring that is stiff to put it in the same place but that creates a bad situation. The lighter, longer spring has stored energy to help rotate, ( lift the front of ) your car. The shorter stiffer spring doesn't help going up and runs out of travel.
Coil over shocks are a good thing, making it easier to tune the suspension. The spring info still applies even to them. What spring rate you need would depend on the weight percentage on the front end.
Look on the lower right part of this web page under Varishock for some spring info.
https://www.cachassisworks.com/cac_tech_articles.html
Hope some if this helps.
Curtis