I've got an SS2 on order, so I've been asking the same question. The links below should help. I've only used the tf-tuned one before, but it's calculations have been spot on with the sunday and socom I've used it for.
http://www.bearandwife.com/bear/cycling/springcalc.html
http://www.tftunedshox.com/info/spring_calculator.aspx
http://www.bearandwife.com/bear/cycling/springcalc.html
http://www.tftunedshox.com/info/spring_calculator.aspx