How do I control the horizon start on M_Sky_Panning_Clouds?

I duplicated the engine sky dome and materials so i can customize it. However I can’t figure out how to change where the most opaque part of the horizon starts in the sky sphere. It seems like I am only able to control the falloff of the horizon and right now it starts out way too thick for what i want.
In general It would be extremely helpful to have more information on how the material M_Sky_Panning_Clouds actually works, it seems to be controlling a lot more than the clouds and I want to understand it better rather than making random tweaks to the curve controls for the zenith/sky and clouds