I’m now working on the headstock of my guitar. The neck is 2-1/8", so I made the width of the base of the headstock 1-7/8", because I want an outline of the headstock that is 1/8". I would use the scale tool, intersect the lines, and clean it up, but the scale tool seems to warp the material and magnifies it, instead of moving on line over by however much I want it to. Sorry if I’m not being very clear, but this is difficult to explain. I’ll attach a picture of my project, and a picture of an actual headstock so you can get the idea.
Also, I’ve been creating things in halves and then duplicating and flipping to ensure symmetry.