Most fuller-oriented mods focus on the body probably because of compatibility and difficulty. That is not very realistic. Of course it depends on the person, but a big body comes with a fat face too. It's part of the package!
I aimed to address this using a new slider for BodySlide adding a double chin which modifies the female head. The downside is that everyone gets this feature, but in the future I'd like to add this as an in-game slider (basically another bone as far as I understand and all the weighting. Might be a compatibility nightmare, however). Regardless, I was delighted to see how easy it was to pull this off!