I'd pick the llghtest one, unless you are want performance weighted toward dual sport, then go four stroke. I've got a 390 and took a short ride on a 350. The 390 seems "quicker" handling to me, which translates to easy handling in tight stuff. I think in reality it carries its weight a bit higher, which makes it a handful when you start to lose it.
Both the four strokes are a pain to pick up when they are down, and over a day of riding tight stuff, a good bit more of a work out. Now, you might not fall over, which makes that point moot. Picking the silly things up is an issue for me, though. The extra pounds in tight stuff are always there, whether you fall or not.