Quote from SmileytopinWith stairs, try making your stairs have a slope of less 1/2 or lower. For example, if you have a staircase or ramp that goes up 128 units, make it at least 256 units long to prevent awkward steep slopes.
http://tf2maps.net/threads/article-stairs-and-your-map.8827/ is about tf2, but it covers the basics with stairs - how to use them, make them, and their shape/dimensions.
I looked it up and took each stair to a height of 8 and a length of 12, someone stated it's the "official Valve scale" for stairs. But thanks for your link, it's quite helpful