Hi Max,
There are a variety of ways to store tubers- whole, divided into small clumps, single tubers, washed, unwashed, treated untreated, labelled or unlabelled; in bags, boxes, peat, vermiculite, dirt, woodshavings, sawdust, Saran wrap etc. For fun, I wrapped some in foil a couple years with great results.

I'd start at the link below. You can also go to the main dahlia forum page here and use the search feature at the bottom using "storing tubers" or similar language. You'll get pages of posts on the subject from this forum.

I'm doing a combo of vermiculite or cedar shavings in bags and saran wrap on others. They've all worked fairly well. Having a dry, non-freezing storage spot is also key.

You can also go to www.dahlia.org "local societies" and click on states near you or not, to read how those growers manage end of season tasks.

Here is a link that might be useful: Colorado Dahlia Society Care and Culture

I seem to be much better at storing tubers then I am at growing plants!!

Last year, I had some very questionable tubers, some where very small, others where given to me nearly dried out or rotten, and I had good success with keeping them overwinter and getting them to eye up in the spring... Lost many by leaving them out under freezing temps to early in the year, did not find the right light for others, oh well, always next year! (Luckally, I did get at least "some" to come up, and boy are they beautiful!)

I take my clumps, semi divide them to a few fingers each, (I prefer to keep some stem on mine). Washed them, then let them soak in a mild bleach solution for 1/2 hour to an hour... Then moved them over to an antifunal bath for some more time... Then let them dry up for a day inside. I packed them up in cardboard boxes full of kiln dried pine wood shavings (small animal bedding). And put them in a cool place. (Some even went into my fridge, but you need to be careful it does not dip below freezing or you risk loosing them!). I checked on them every month to six weeks. If they looked like they where starting to dry, I would soak them for a few hours again and then let them dry, and pack them up again...

Did the same for my Cannas, but there is definately not one way to store these tubers... Perhaps you want to try a couple different methods... I would think a plastic container like you suggested filled with shavings would work rather well. You just don't want the humidity in the box to get too high or you risk rot.