Check out Race-tech. When you go there find the Spring calculator, I think its called. It will ask you what bike, your weight w/gear and riding conditions, like motocross, trail, supercross ect. You can guess for the most part, at which describes you best. Then it gives you your stock spring rate and their suggested spring rate. You can get one from them or use their info to know what you are looking for. I cannot say for sure what springs are interchangeable on the mimis, but I know that some will. You might find a deal on ebay. You might also try to find someone to recharge your nitrogen. That will help your shock performance for very little cost. The best thing would be to have someone adjust the spring and to revalve the shock. That would set the shock up for you specifically with all of the adjustment you need. I would not overthink all of this though, if I am guessing right, I would say you are gona outgrow the 60 by next season, if you haven't already. You might start thinking about an 85 which will haul you around for a long time.....