I just had a thought; None of my builds are S&G, at least so far. I glued chine logs and inwales to the sheer planks while they were still flat. This stiffened them so they were easier to handle without a helper, and probably explains why, on my fist boat, there is no visible trace of a flat spot at the joints despite the butt blocks inside. Does that mean I was cheating, or just very cunning? The butt blocks near the bow are also behind the foot rests so I don't see them when I am paddling. The only time I notice them is when the boat is hanging on the wall in the workshop during the Winter, and they soon disappear under a patina of wood dust . . .