Procomp is a UK outfit that builds and supports a lot of car in the Locost race series. I have been talking to Matt one of the founders about building me some shocks. He is not building shocks anymore because of poor health. We was good enough to give me the specs of how he build shocks, I am going to get a set of shocks built to his specs, the information he gave me does not make sense to me I hope it does to an experienced shock builder. But back to sprint rates: for the front it depends on your shock angle from 30-45 degrees the rate is from 325-400, for the rear it's 150.
Graham
http://procomp.co.uk/https://youtu.be/NnEH1ac6BCE