I am making curtains for my kids' room, and the one and only fabric they can agree on is a quilting cotton with a 110cm width. It has helpfully been discontinued, so I can only get enough for 1.5 fullness, and the Internet tells me I need 2x fullness or they will look "skimpy". I'm planning on interlining with cotton bump, and putting blackout lining on too. Do I really need 2x fullness??? Really???