I think your tutu looks really full. The other pic maybe it's a double layer or triple layer tutu...I can't figure those out either.
Maybe it's the angle of the other pic that makes it look fuller than yours also your angle of pic is different ykwim?
as for the petti tutus..I've been searching for a tut I'd buy one and couldn't find one. there is a thread on here discussing how the bottom was tied...if I find it I'll come back and post a link.