If you are going to be daysailing and weekending in places where the weather forecast might have you stay home or get a slip the smaller anchor will be fine. If you might be caught in an open anchorage in some wind you might sleep better with the larger hook.

My boat is about the same size and displacement as yours. I use a 55# (25 kg) Rocna (Canadian for what it's worth) with which I am very pleased.