"Long skirt" - From below the knee to the floor. If you use "((long skirt))", it will be guaranteed to be to the floor.
"Mid skirt" - It was supposed to be at knee level, but it is very unstable in length. It can be short or long.
"Mini skirt" - From mid-thigh to short waistband. If you want it shorter, use "(Mini skirt:1.5)"/":1.8"

For "full body" it is still better to use "Face Fix"
Sometimes it's worth specifying "((Long legs))"