OK, attached is a video of what I doubt is a very original idea, but if nothing else its new to me. Not the concept of differentially sized layers of IX, but of building it inside out like a stuff sack, turn it right side out, then just finish the one end with a rolled hem. Sew a channel on the foot box for a draw string and voila quick and dirty top quilt. I suppose you could even turn the rolled hem end into the draw string channel? What I really wonder is, if you scaled this up to full size is just one inch difference between the IX layers enough, or does it really need some darts or something to give more gap between the layers? Open to suggestions.