Domes aren't staying coloured after restart. Looks like the data file is reverting back to default.

The "domes" are simply prefab entities that exist within the game, nothing more.  The only reason color options even exist is because they're already in the game. 

One COULD utilize shaders to create domes, but the load it would put on your client wouldn't be worth it, and it would take a fair amount more coding which isn't even necessary.