I bought a large piece of white foam insulation from Home Depot and cut it into 4 pieces which measure 14.5" x 48" and are propped up against my dining room wall. I pin directly into it with no flannel. Because there are four pieces, it's easy to store them in a closet. I don't use the wall for spray basting for the reason your husband suggests, and prefer to lay down a large sheet of plastic in my living room (no garage available) and spray on that because then the spray is directed downwards and not at breathing level.