Looks like your doing the homework necessary to find a good starting rate. My method was a little simpler - I called the guys at Poly Performance and gave them a wheel-by-wheel weight and shock measurement with the first set of springs to determine the optimal setup. I'm currently removing and redistributing some weight since I first set it up and will need to address the spring rates again.
Since I know some of those guys on a first name basis and visited the shop many times I have developed a great relationship with them. I would think they would be willing to give you a second opinion on any spring rates you pick.
Since I know some of those guys on a first name basis and visited the shop many times I have developed a great relationship with them. I would think they would be willing to give you a second opinion on any spring rates you pick.