It really depends on the tree and the weather. If the tree has a lot of branches on it, I can use them to get higher. If it's early season and I am not wearing a lot of clothing, I can space the rails out farther. The lowest I have been is 18' to the platform of my stand. The highest I have been is 25' to the platform. The best thing about the rails is the ability to move them around the tree as needed to get up and around branches. I posted this picture before but here is one of my setups from last year.
