Check out the shapes of the studs. On Innova tires the stud is just one big block of steel (unless they've changed them since I bought mine), on Nokians the stud is shaped and has a sharp point. Thus, I would expect the Nokians to be the better tire. 2X better, I don't know.
How much ice is there on your trails? If it's just frozen dirt, even if it would be very wet if unfrozen, I doubt studs will be worth it, keeping in mind that studs offer no advantage in snow.