I've just made a tulle underskirt for my six year old and three year old granddaughters bridesmaids dresses (which I also made). I used a very soft tulle and used four widths of fabric for the bottom layer, two and a half widths of fabric for the middle layer and two widths of fabric for the top layer. my daughter in law didn't want the dresses too sticky out'y, but simply wanted to give the dress some fullness, as the dresses arent floor length, (mid calf) she wanted the tulle visible below the length of the dress too, so I made it longer, than the lining. this image shows the dress before the over skirt has been added...