Well ..I just spent 1/2 an hour trying to download pics of the correct mathematics for you to calculate the correct spring rates. My engineer gave me the formulas . he also sent them to East Coast Suspensions and told us both to work the math. A week later we compared 3 separate results and they all came in the same . Alas this site won't let me down load pictures of the calculations. I apologise for not being able to help you. I haven't driven my car in anger yet but the very few times I've had it on the road . It handles well and rough roads are soaked up nicely. It might prove to be a bit soft but that can be sorted with sway bar adjustment. My car is an RMC .. heavy (about 1200 + kg) but stiff. Good luck with your works. The suspension companies' name that I dealt with is .. East Coast Suspension
sales@eastcoastsuspensions.com.au www.eastcoastsuspensions.com.au