I find that most women, when they purchase a kilt skirt from the museum, choose a length somewhere between the bottom of the knee and the middle of the calf, which seems to be a nice, conservative length.

Most of those opting for a "hostess skirt" (full length) are looking for something to wear to formal occasions, not Highland Games.

Some do choose the top of the knee, because they want their skirt to look more kilt-like. (Some choose top of the knee simply because they like the length).

And then you always have those who want the skirt as short as possible.

I actually find that most women who come in to be measured for a kilt skirt already have a strong preference as to the length of skirt they like to wear and tend to order their kilt skirt along those lines. As I said at the top, somewhere between the bottom of the knee and mid calf seems to be most common.