I built a Yare and I love the light weight for the same reason you suggest. Mine is 27 lbs. I didn't do anything special for light weight and I have never felt the boat was not sufficiantly strong for what I do with it, Day paddling on the Chesapeake Bay and its estuaries.

For my 175 lbs, Yare is a tippy boat. It took me year to get comfortable with it. I had to learn to roll to feel really confident going out in any kind of waves at all. Even now, it is a lot of work staying upright in anything over one foot wind waves. I note my son at 90 lbs finds it much more stable than I. I am probably over the top on the limits on this boat. 150 lbs is probably more like it.

Yare is also a hard boat to make comfortable. The seat needs to be as low as possible for stability. I use 3/8" mini-cell glued to the hull where my butt bones hit the hull, ooch! The deck is fairly low and the fore & aft cockpit carlin lands right where you're knees want to be. I carved out the beam at that point, but what I really need to do is install some leg hooks ala Shawn's post this morning.

Still, I love the light weight and the speed of Yare. It also rolls nicely. I find I keep coming back to it and am still trying to work the bugs out.

Craig