Getting help in this community is like pulling teeth, I swear to god.
Anyway. Windlight settings.
Noone seemed to have any answers, so I am sharing what I know.

Officially, opensim discontinued Windlight.
http://opensimulator.org/wiki/LightShare
You can still enable those settings in OSSL and OSSLDEFAULT config files. You used to have to enable them in Xengine settings but Yengine doesnt seem to require it.

The default settings that come bundled with Firestorm, Singularity, and Coolviewer are buggy AT BEST.

Region weather settings are saved to whatever database you are using in your server in a kind of strange, sloppy way. It isn't 1:1 with SL Windlight settings.
You're actually better off editing region windlight settings with a script than attempting to change them with the viewer.
https://www.outworldz.com/cgi/freescripts.plx?ID=1122

You can edit this script to get the job done. If you are using Windlight i really recommend using the singularity viewer- it seems to play nice with Windlight.

Also, after hitting an option to change the windlight settings... hit 'world', 'region/estate'. For whatever reason this triggers a refresh of the windlight settings on the region and you can see the changes you've made.