It really depends on how much oak flavor you want and what type of oak you're using. If you were using a medium toast, I would add 1/2 oz for a 5 gallon batch. Leave the beer on the oak for a week and then taste it. If it's not oaky (is that even a word?) enough leave it for another week and so on. VERY IMPORTANT, you can always add more oak flavor, but you can't take out what is there!
You can't be a real country unless you have a beer and an airline. It helps if you have some kind of a football team, or some nuclear weapons, but at the very least you need a beer.
Frank Zappa