Keep an eye out for 45 gallon size parts cans from your surplus sources.
Usually a rubber donut seal, and a lever operated ring clamp to hold the lid on.
Airtight, reliable, and spacious storage.
A couple dessicant packs into one of those, and your moisture issues are done.
Or you could find a couple engine cans (aircraft engines, tank engines, etc). :-) Not real convienient to get open, though. But they usually have a vaccuum guage on them to see if they have been leaking.
Cheers Trevor Jones