IMHO, fit is more important than paddler's weight. For sea kayaks with lots of volume in the cockpit and hatches I find that almost anyone who fits the boat properly, also enjoys paddling the boat, regardless of their weight. The difference might come at differentiating whether you will be using the boat for day trips or for multiple day trips or both. For these decisions, your weight is more important. Most paddlers I know, either don't camp at all or they take maximum of 2 camping days (weekend). I am a fairly heavy paddlers yet I have an 18 foot boat with lower back deck that is just about at it's maximum with me in it and with a few basic safety items, a snack and water bottles. I only use it for day trips and I like how low in the water I am with this boat. My second boat paddles best when loaded with more stuff. Except for winter I use it for all my camping or extended day trips when I take more gear with me. It is my favorite boat yet I don't use it all the time. My third boat gives me a little bit extra room in the cockpit and I find it most comfortable to paddle in the winter with extra layers under my drysuit. All of them are between 17-18 feet, with cockpit accommodating my size.