I have been using 2 seperate sheets of it. One for the warm side and one for the cold side. Because he has not messed up both sides yet. So it makes it really easy to just replace one side and not have to re do the whole cage.
It makes it really simple since he seems to only mess up his warm side about every 3-5 days. And yes its very easy to spot as long as you don't spill any water on it.
I curl up the sides to prevent him from getting anything into the corners. But by doing this it seems he was able to get under it. So I just made it so the deco weighs down the corners.