I just turned the scattering and ground reflection way up, and everything else way down, basically. I've found that different settings are required for realistic sky at different times of day and at different altitudes. I could record my these settings at intervals in time and altitude, every hour and maybe every 5000 meters, and create a look-up table of optimal realistic environment settings, it might be a good reference for rendering videos, or maybe it could be plugged in to OT, to interpolate between the intervals based on the current time of day and altitude and automatically adjust the settings. Especially when going from sea level to a very high altitude, the desired settings are very, very different. Scattering is good at sea level, it makes all the atmospheric settings enhanced, but when viewed from space, Earth is shrouded in a uniform haze which is inpenetrable. Also, if you change the time of day in space you will notice the settings need to change slightly, although not as much as is needed to account for change in altitude.
Here is a screenshot with the environment settings I used, and a sunset time lapse video. (I preemptively apologize for the glitch-y audio and poor quality encoding, it is my first video attempt)
Outerra Anteworld - Sunset Timelapse Over Talkeetna Alaska Regards,
Uriah