[Quester]

Preflop, definitely make it $2 to go.

On the flop, you may want to pot this since you had 2 cold-callers. But I don't think your bet size was necessarily too small. After Button wakes up I'm shoving just as you did. MP has put dead money in the pot, but I want this heads up. Good thing for you the cards made your runner-runner straight.

As far as buy-in, you should always buy in for the max unless you have a specific reason not to. Playing with 100BB gives you an advantage over other players, because you're better than they are post-flop.