I am having hard time finding the proper spring rate for my rear shock. The spring on my bike has no marking on it, so I don't know what it is, but it is way too stiff. I am not able to set a proper sag. Does anybody know what spring to use for my weight ( 155 lb without gear and I use the bike mostly for desert riding ), or how to find the proper spring. I think I would like to try the progressive spring, but I am open to suggestions.