First, you probably know this Ud luz, but make sure that you are recognizing the difference between N/mm and Kg/mm when you're dealing with springs, both in this discussion and when ordering.
The N/mm to Kg/mm conversion is 0.10197. So in my case, I had miscommunication with the Dealer - I asked for a 5.4 N/mm shock spring (when I meant 54 N/mm - no decimal) and he got me a 5.4 Kg/mm spring, which is only a slight step above the stock rear spring (which is 52 N/mm or 5.3 Kg/mm).
Some confusion also exists in this thread where you mention 54 N/mm for the forks, and we are assuming that you mean .54 Kg (which I agree is way too stiff). A 5.4 N/mm fork spring would be too stiff also. The GG manual that I have shows recommendations in N/mm, which is the "less common" designation used.
A second question - are you 205 lbs. with or without gear? If that's your "dry" weight (no clothes), add 25 lbs. for gear. The answer to that question obviously changes things
I will try to attach a chart and then post again with later with my experience.
Jeff
GG Spring Rates PDF.pdf