Coming from an Heirloom background I used a LOT of starch for sewing techniques. The way I was taught was multiple layers. Spray just until damp, with your hands kind of press/pat the starch into the fabric, let it stand for a few moments so the starch can penetrate the fabric fibres, then press on the other side of the fabric. Letting the starch penetrate the fabric and pressing on the opposite side you sprayed will alleviate the starch sticking to your iron and won't leave all the flakiness because the starch has penetrated the fabric fibres. HTH