NEARLY FINISHED DELPHI'S FLOWERGIRL DRESS

Hi Cuties, I am requesting some help. I'm making our grand-daughter's flowergirl dresses for Amy's upcoming wedding in May.

I have the pattern as shown below - but Amy wants the skirt made in Tulle. She wants 6 layers - eg. say 3 pieces between 12 - 15 inches deep (folded in half) to give it fullness.

So my question is how much fabric should I cut for the waist measurement (which for Ophelie's size on the pattern is about a 24inch - it's then gathered onto the bodice) For Delphi she is only 3, so it will be smaller.

I hope you understand what I'm trying to say. Basically I need to know how wide should I cut the tulle to give it a lot of fullness. I know when I used to make curtains it always said to do them double and then a half to give it fullness.

Any help gratefully accepted. Love Chris

Picture 1 is the Pattern I'm using
Picture 2 is the skirt pattern pieces
Picture 3 is the practice dress I made for Delphi in 2015

The bodice is going to be Lace lined with a soft stretchy fabric. The Ruffle and the Bow/Sash is Raw Silk and of course the skirt is Tulle.

UPDATED: I've put up what we've done so far. I haven't finished it, but you get the idea. I have to hand stitch the raw silk ruffle down and put a button on the back and finish up the end of the sash etc. It looks gorgeous on Delphi. Tomorrow we are doing invitations! I'll see how we feel tomorrow with regards to making Ophelies.