Don't give up on the dries, thaxor. I would say that Sg's estimate of the general productivity is probably pretty close, but when you get one of those 5% moments (you'll know it by the once quiet lake becoming a myriad of ripples, rises, and splashes), you'll be kicking yourself if you don't have something dry to throw at them. Sometimes, I'll bring two rods with me, one set up for dry fly fishing and the other for nymph/streamer fishing. That way, it's not such a hassle to change up your tactics on a second's notice. The trouble (at least for me) is that I still haven't found a great way to keep the non-fishing rod out of the way on a pontoon boat or float tube, so everything but the switching can be a pain.