In place of an actual quilt, I have styrofoam panels (from Home Depot) that I covered with decorator fabric. These slip into the windows at night to block the night's colder temps. They just "friction ft"- no hardware needed. They work so well that there is ice on the INSIDE panes of the sliders and windows! Removing the panels in daytime allows that moisture to evaporate back into the house, where the moisture originally came from.
As to the stash: storing it against an outside wall adds a layer of "insulation" between you and the wall- that's my story and I'm sticking to it.