I use the Rustolem because it's easy available....It's Cheaper and it works well.
No need for flattening agent. Think about it.....In order to be highly reflective and shiny.....a surface must be slick and not a lot of orange peel. The non skid does just the opposite. Use a West system foam roller to apply. It will be a little more aggressive at first when your done, but will wear to a perfect nonskid.