Not sure why you are in such a rush? But personally, I would just try for these when Cata launches especially at midnight/3am/6am/9am during the first few days after launch, everyone will be so busy doing the new zones/quests etc...
I doubt many people will bother with the Arena once Cata launches, what with all the new stuff to do. I would`ve thought the first 3-4 days you will have it prety much to yourself, bar maybe other twinks. Guess we will wait and see