Distractions

I am finding it hard to ignore this.

I'm not allowing it to stop me working on this though, and am making fairly good progress. My main dilemma is when to begin the cast off for the handles, since I have no more yarn than the ball in the picture, and since it's a hand dye, it's not easy to buy more. How do I know how much is going to be needed for the handles?

How much yarn is enough?