Running 18k up front and may go up to 20k but I am an autocross sea urchin.
The nice thing about Fortunes is they have a crazy range of rate they can take before needing to be re-valved. Plus or minus 8k or so. If you get them be sure to pick up some bump stops and helper springs. Helper springs will really help with allowing the car to drive nicely on the street with higher main spring rates as they allow you to keep a good amount of droop. Bump stops will allow you go low without the risk of slapping chassis or having the tire rub the fender/bumper bracket.
Springs are easy to change. Get a good starting point and then learn what you like or dislike and make appropriate changes based on how the tires heat up and wear and how the car is driving.
As for divorced (oem type) vs true, I don't think it matters too much. I run divorced style cause of the da rules. Going true type changes the motion ratio so it will require you to run much softer springs in the rear.
I would start at 16k front and then depending on the rear coilover type you go with 14k for oem/divorced rear and maybe 5k rear if you true style. that will put you on the lower side of 2 hertz front and rear (2.2fr/2.1rr give or take a .02 or so depending on how heavy your wheels and brakes etc are)
Cheers, and remember, don't stress too much on getting it "right". Chances are wherever you start will be wrong. Spend more time learning how to understand what changes will do to affect how the car handles.
