Keep in mind that generally Proof sets from the mint are not air tight and some of the coins may tone no matter how to store them . Best to keep them in original mint plastic and I would keep them in outside packaging so they don't get scratched or marred .
Always good to store any coins in the best environments away from humidity , extreme heat and cold temps . If you must display your proof sets then Bumps link sounds about right .
In Memory of Butch L.
and Jim U. rest in peace .