The RX8 spring rates wont be relevant here - as it has different suspension setup the spring rates could be hugely high and still softer feeling than a 200SX, or the other way round, depending on the lengths of the arms and how they're all configured etc.
Just my 2p, try and stick to comparisons with other 200s
12/10 on a 200SX is very stiff. DW CS2 I think are 8/6 as standard, and many people find them a little hard riding, although I loved mine. Apex do comfy/limo spec as they call them at around 4/3, so somewhere between those two would probably be a good shout.