I have only spray basted once. I laid table runner on driveway. I believe the can said to spray the batting. I think you fold it and spray half, smooth it together then do the other half, then spray top of batting and place top on 1/2 at a time, smoothing over and over with hand and arm until very smooth and taunt.
Wonder if there is a you tube on this subject....bet there is. Think I will check it out later TODAY! I stayed up so late it is Thursday already.