Question

What’s the best practice for drawing a closed, filled path where each line has a different stroke?

Answer 1

Fill the complete path, then iterate on its elements to stroke one line segment for every lineto and closepath (see actual Quartz names here). Your applier function will need to keep track of the current point itself.

Of course, if any of the elements are curveto instead of lineto, you may be screwed, but try it anyway.