I have no idea what's recommended, but I had a Pelican 1120 on hand, so I pulled out most of the foam center, put a couple dessicant packs on either side, and put a couple 10 packs of vials in the middle, tossed it in the freezer. Theoretically seems like it should work fine.
Been reading on what to do to avoid condensation issues when taking it out, and seems like if I let it come to room temp for an hour or so before opening, that should help. I'm considering using a smaller secondary case to store maybe ~3 months worth so that I wouldn't have to open the 1120 as often.