Here in Taiwan is really humid, I use a massive off-brand tupperware as a dry box. The box has a soft plastic bottom, like the ones you can find in fruit boxes. And a couple of dehumidifier (or dry box) inside. I bought a couple of hygrometers (to see the humidity) one is outside and the other one inside. the outside one usually marks 80% the inside one usually 35-40%.
For the film, the same, but smaller, inside the fridge or a cold(ish) place.
Really cheap DIY drybox.