I find yellow to be a real pain as well, which is partly why I challenged myself with these figs. It seems to me that of all the colors, yellow is the one most influenced by mixing, so it's very hard for me to blend shades for highlighting. I typically get around that problem with 'impressionistic' yellows that visibly mix oranges and browns, but on the advice of a friend have started shading yellow with purple, which seems to work without giving the yellow a muddy or muted quality.
It's tough for me though since I usually start with the shade color and work up, rather than start with a base and work into shadow. I'm pleased you like the end result!