I tried a 62/54F this weekend with the stock TSS 04 blue/black stripe spring on my X with stock gearing this weekend. Was also using a 120-310 primary spring with uncut 10-72 weights. Seemed to pull good, but didn't have a mule to test against. Pulls 8200 from a launch with this setup. Heat on both clutches was minimal, unless doing a 3/4 mile long WOT pull. Then both clutches were too hot to touch for very long. I did both on trail and off trail riding with this combo with 6" of fresh powder on top of a hard base, was pretty happy overall. Also tried this same setup, with the exception of a 140-240 secondary spring. That combo gave 83-8350 WOT rpm. A little too high with the stock pipe according to the gurus here.