I don't have Elf, but I have many other HSS characters. IME, it's not easy to fit a dress to them. The problem is that Ingrid completely reshapes the ribcage, hips, and breasts. Generally, she makes the character more slender, and lifts the breasts so they look more perky and youthful. It looks lovely. But when you try to put a dress on them, the boobs pop out, because they're so high. The standard breast morphs don't help, because they make the dress bigger in the wrong places.

With the Tailor, you can get dresses to cover them, but they end up not looking that great. At least, when I do it. The morphs are so extreme the dress mesh can't take it, and ends up looking stretched in some places, wrinkled in others.