Thanks, Michael.

That entire area there should definitely have been planar. I went back through the construction, and it turns out my initial top profile was definitely not optimal; composed of multiple collinear segments, when a single segment would do. I think a similar cause might be leading to the naked edges at the nut (opposite, narrow end of the neck), as well.

I'm simplifying those curves and focusing on doing larger planar sections where applicable. I see it's definitely easier to get lax about the underlying topology compared to something like subsurf or direct spline patches where you live and breathe the grid :D