Vintage Dreamy Dress – Help Appreciated Sewing Machines Parts and Sales in Los Angeles

I found this fabulous dress on Etsy awhile ago and fell in love!

Sadly, it was too small for me, but I kept it as a reference. My question is – how much fabric do you think I’d need to complete the bodice? I am currently scouting out patterns to help, but I may resort to just ad-libbing it with an old bed sheet.

Also, I always thought that chiffon would fall apart if not hemmed, so am I wrong, or is the skirt made of something other than chiffon? (Seller stated skirt was supple chiffon).