Another approach to this is to make a Library Clone. File > Library > Library Manager. Select a library on the left, the use the Clone Library tool. You can then switch to this library and do changes there to test them.
The only gotcha might be if you are planning on changing or deleting file tags. If your library is set up to write Library changes to File Tags, then those would get written to your media files, which is probably not what you want. Otherwise, if it's just settings, you should be ok to experiment in a Library Clone I would think. Though I have to be honest and say that I haven't personally tried this, so it's just an untested idea.
Brian.