Re: 2wt line on a 3wt rod?
I've been eyeing that Carbon 6'6". What a nice rod! My buddy has it and it's sweet.
It's possible to underline rods, I do it frequently on my softer action (aka glass rods). For the Carbon, I don't know how well it'd throw 2DT...maybe a 2WF but I think it'd perform better with a 3wt line.
Just my conjecture...but if you've got the line and the rod, give it a shot before you buy new gear (says the guy who's reel collection grows every week)