Re. Lean factor, I imagine that the lean factor is the tangent of the angle as you've been using it. tan(45) = 1; I had to do [Win]-[R] calc [Enter] to find the other ones, but the angle corresponding to a lean factor of 1.27 would be about 51 degrees, and the lean factor corresponding to 16 degrees would be about 0.287. That takes about 5 seconds each, if you know how to do it. I'm a math major, so perhaps I have an unfair advantage--but 45 degrees mapping to 1 just screams "TANGENT!" to me.
It makes sense, really: a lean factor of 1 tilts a vertical face over as far as it is tall; a lean factor of 2 tilts it over twice as far; etc. Planetside could include a built in converter, but it's really not hard to figure it out yourself.