In my experience, that mojo spring calculator is as wacked out as typical mojo stuff.Calculator says it should be 400lbs. I hope local Fox distributor has both 400 and 350lbs springs.
The TFtuned one has been pretty much spot on for me for several differnet bikes with different shocks and suspension designs. If your round appropriately for you riding style, and falling/rising rate design of the frame, it has been pretty much spot on.