Recommended weight: 0.8-1. Model for the OC siblings based on Monster Girl Encyclopedia, princess Mari and Rune. The "demon girl" tags bias towards black wings first, so you might want to add "white wings" and "white horns" to avoid any trouble with colors. Should be flexible for styles and outfits. The characters aren't equally balanced, Rune has a lot less data, so try to find your ideal weight for each.

Princess Mari:

mgemari, demon girl, solo, white horns, white wings, white tail, white hair, long hair, black sclera, red eyes, sunhat, white dress, sleeveless

Rune:

mgerune, white hair, bangs, twin braids, hair ornament, monster girl, white horns, demon wings, demon tail, sweater, shorts, thighhighs