It depends on what kind of effect you want. I quite like Sickly Skin for highlighting Moldy Ochre - it has a very subtle greenish hue, so you end up with a slightly paler result. If you want a warmer yellow, Menoth White highlight is fine.
These were painted with Moldy Ochre highlighted with Sickly Skin, if you want an example of what I mean. (The shading was done in layers of turquoise and purple, don’t remember exactly which paints.)