Choosing spring rates for mostly a street application comes down to preferences and comfort. If you're never going to get serious about autox or track stuff, don't focus on going crazy with the spring rates. If you don't plan on being competitive to the point you're doing events every weekend and spending thousands of dollars, there's just no point. So focus more on what would be comfortable for you on the street. If you drive a lot every day, esp on roads that are bad, I might say 380f/250r. If you can bare the road imperfections and maybe don't drive a whole lot on bad roads, then maybe 380f/350r. If you plan on lowering the car quite a bit, then maybe 430f/350r.
These are all only suggestions from my personal experience. There is no real right or wrong when choosing spring rates. It comes down to personal preference and the only way to determine that is by picking something and trying it out. What one thinks is bearable and comfortable could be too harsh and uncomfortable to another. The great thing about the GC setup is you can just buy new springs with different rates until you find what is comfortable and sell your old ones and not lose a whole lot.