Leopard geckos need a minimum of 3 hides. 1 heated by a heating mat around 90°F, 1 close to the hot hide with damp paper towel as a moist shedding hide, and 1 cool hide on the farthest side if the tank from the heat mat.
Reptile bark is never recommended for leopard geckos as it can injure there soft underbelly and feat. They can also eat it and that will lead to an impaction. I wouldn't recommend any lose substrate. Instead, stick to a non adhesive under counter lining. It is cheap, comes in a variety of natural colors, easy to clean, and best of all has no risk of causing an impaction.
