I do about 10" from the wall and then every 20". While I know a lot of people do the leaning ladder style I found that it didn't really work as well for my birds. See it is natural for them to try to roost at the highest point. Therefore MY birds spent too much time/effort arguing over the "best seats in the house". Once I set it up so all roost are on the same level bed time goes much smoother.
This info is simply provided based on my own experiences. One thing that I think all will agree is make sure the roost is higher than the nest boxes.
Opps I guess mine is not up to par. Our roost is level with the nest boxes. But we needed it low enough that the silkies could get on it. And they do.
