FUEL: REFUELED is an enhancement modification for the game FUEL, which brings multiple bug-fixes, improvements and the addition of various new content.
The advanced editor is very similar to the basic tool I showed in a screenshot yesterday, however it gives the user a number of additional options. Whereas the basic editor will only allow a global value to be set... the advanced editor allows the user to set both the start and end values. An example of when this would be useful is when you want the challenge to be really cloudy at the start of the challenge... but then much less cloudy towards the end (i.e. different values of weather).
Upon simply entering all the values in this window, the program will export a script into a mod folder, containing all the necessary files and directories (and even a JSGME friendly description), so all you have to do is open JSGME and enable it.
This program will only export to the MODs folder and thus it is not capable of interfering with the base game files in any way. The only circumstance to which would overwrite a previously stored file is when you specifically tell it to overwrite one of your previous creations by giving it the same file name.
If you want to take stuff further than this tool... you can then just open up the exported script in something like Notepad++ and play around with the values.