You can switch it only in CM. So just do an Alt-Tab while ingame and open CM. Then switch the versions in weatherFX.
If the custom_config (lua) is located in "/extension/weather/sol", it will be updated with every change...
Thanks. Thought one of the in game apps had the switch. Never thought of the obvious way to do it.
I think I understand about the custom_config. Will try it out and see what happens.