I took a class from Jeff Putman a while back, he recommened at 7wt Spey as an all around rod.
He aslo recommended at MOW tip of 5-float/5-sink on the Am. in the winter when the flow was around 2000 cfm.
I agree with hwchubb; a sinking poly/versi leader is enough to get a fly down on Am. at typical flows.
If I was every lucky enough to hook into one of those 10+lb fish I wonder if I would wish that I had the 7wt.