Aging cider in mini-barrels?

On a trip to Tennessee this weekend I scored three one-liter mini-barrels really cheap. (Would you believe Jack Daniels charges more for a one-gallon barrel than for a full size one?) They need a little TLC so at the moment I'm rehydrating two of them with water and a crushed campden tablet. The third one doesn't have a tap, so it's a project for later. Hopefully in a day or so they'll be completely watertight.

I have some still dry cider that has just recently cleared and is ready to rack/bottle. I want to try barrel-aging some, mainly just for fun and to see if I'd like to maybe invest in a bigger barrel. Has anyone else done this, and if so what were the results? From reading I know that small barrels have more oak surface area per volume of cider, so oaking is faster than with large barrels. Any suggestions as to how long to leave it? Since they're so small and they have taps I'm thinking of leaving them a few weeks and serving from the barrel.

how do you prevent oxidation when serving from a barrel? this has been bothering me for a while, since many english ciders are served from giant barrels and don't seem to replace liquid with an inert gas.
sorry no insight into barreling

I'm honestly not sure about that. I don't think it will be an issue with these tiny barrels, as they won't hold more than a few drinks each. But I've wondered about that for larger barrels. I suppose if this works out and I go to a larger barrel I'll just use it for aging and then bottle the cider when it tastes right. I have read of a few people who keep a pipeline going and keep the barrel topped off with more cider as they dispense it. That keeps O2 out and keeps the barrel hydrated so it doesn't leak.