Hibiscus Red S4

I searched the archives quite a bit and found TONS of information, all conflicting about tire pressures. I know reccomended is 36/F and 34/R of course cold. I'd like to dial out some understeer and improve response. I'd be willing to sacrifice some ride quality. Obviously, this requires raising pressures, but how much? Also, would anyone still reccomend running the rear at a higher pressure? I'm running Toyo FZ4 M&S All Seasons with plenty of tread at 38/F and 36/R now. Thanks!