You will need to know your suspension type, sprung weight, unsprung weight and spring angle then
calculate. By playing with the spring angle in the calculator and the motion ratio it is easy to see what a difference it makes.
It's not something we like to talk about but you want about 40 - 50% droop
Simply jack the car up and use a set of bathroom scales to weigh the unsprung weight of each corner. Sprung weight is a bit harder and may require a trip to the weigh bridge or an educated guess.
I used this method and it is spot on and my car sits and rides perfect.
QA1 shocks and springs get the big thumbs up from me.
Dynamic weight distribution is a whole other topic.