Ganache (the creamy stuff inside): 12oz of chocolate for 10oz of heavy cream or "creme fraiche" (I prefer heavy cream). Grate the chocolate and melt into the heated cream. refrigerate.
For that quantity of ganache: 1lb of chocolate for dipping. melt this chocolate, make balls of the ganache and dip them into the chocolate.
I tend to keep them in the fridge (I prefer to have the ganache thicker/harder).