The height scaling in Toon gen 4 seems based of age 21 instead of age 40, if you also have those assets, may be worth a look.
Been looking at this myself, as setting age to 19 doesn't really give that look. I'm sure if people had a look at other toon styles, they may notice that college age has a more youthful feel that you'd attribute to college students in media, well until you walk on a college campus and see just how young that really is, and understand that TV/Movie actors portraying college kids are in their late 20's and 30's.