This is 1/2, and the OP did not specify if he's doing 6 max or full ring. If it's full ring, 300BB is plenty for 1/2. There are enough horrible players and donators that even a downswing should put you in decent shape. Short handed I think 1k would be in order. Remember, he's playing at 1/2, not 10/20, the games are more passive and there are a lot more fish, and way fewer sharks. This will "pad" downswings and keep them from being as high.

-dustyn