I got a clutch from FAST and at first I thought about just using 3, but after talking to him I went ahead and threw them all in there (he didn't talk me into it really, just gave me the idea that I might as well use them all). At first I noticed it was some stiffer, and on the first ride I could tell. But after that first ride I never could tell again. Just feels like a clutch to me, and my arms will be dead tired long before my hand is from pulling in the clutch.
Point is, just use them all, its not that much stiffer.