Is it critical that a solar cover reach to the edges of the pool? We can purchase a solar cover that will reach 6" from each side that we won't need to cut to fit. It would also leave the steps open (we have a 17X36 inground pool with vinyl liner and fiberglass steps). Will too much heat escape through the open edges and step area? Should we go ahead and purchase the larger cover and cut it to fit? Thanks for your advice.