The only thing I'd say having run several 6 degree sleds, including super vees, is that shallow degree boats will beat you up in mildly choppy water almost like a flat bottom. I think that's why you see more and more CR guides going to variable degree boats like the Raptor.

Now, if you want to fish the tribs and not just the Columbia, a 6 or 10 degree boat is likely a necessary compromise. But if you're mostly interested in big water fishing and want a more comfortable ride I'd look for a deeper hull design - 12 degree or better. But to find something like that in an older hull, you'd probably be limited to mostly foward helm boats which would be an even bigger boat project.