12 bolt carrier questions

[72LB]

I'm getting ready to put this back together but aren't sure on stacking the clutches. The kit has 3 clutches and 4 plates per side but from what I've read a clutch has to go against the back of the gear, is the extra plate not needed? It's alot smaller a stack for the clips without it too. Also the book I have says reuse the shims that were on each side, is that ok or would it be better to use the new shims from the kit?