I have a question about storing the liter of nicotine I recently bought from MFS. I want to transfer it into 4oz amber glass bottles and store them in the freezer. Should I fill the bottles all the way to the top of the rim so there's no air, or should I leave a little room for expansion? I don't know if nicotine or the PG will expand so I don't know how much I should fill them. Thanks. 