For those of you who wish to have a different sky file refrenced in your LUA for different gamemodes, there are a few things that xwingguy overlooked in his post on the first page:
1) You DON'T put the sky folder in the world 1 folder. If your map name = ABC, you put it in the data_ABC/worlds/ABC folder (in other words, 1 above it)
2) The sky file in your world1 folder is STILL REFRENCED, so what you need to do is a) copy that file and paste it into the sky folder and incorporate it into the system there, like xwing said, then b) in the origional one, in your world1 folder, delete all the data that you want the others to cover. For example, delete the dome that it refrences, because it will then load two of them, and all you'll get is a black sky.
But I can attest to the fact that this method works. Thanks a million, xwingguy!