You can make either type any weight you want to make them. The variables are dictated only by what you are looking for in a design. Lightness should be only one of the characteristics one looks for in a boat and should be weighted according to the design parameters. All in all...the lighter you can make it and still meet your design requirements the better. A more experienced builder using the same design and materials can make a lighter, stronger boat than an inexperienced builder. And, generally, if I'm trying to make the lightest, strongest boat I can for a specific purpose I'll use S&G. Not because it will be better, but because it will be quicker, cheaper, easier, and still suit my purposes. This is just my observation...of course.