Blendshapes are pretty easy to do the only time consuming part it shaping the model to get the look you want....
All you do is make a copy of you original geometry adn model it to the way you want. Then select the copy then shift select the orignial go Deform> create blendshapes. Then Sliders come up.


I do all my shapeing in sub-d then covert back to poly add a smooth for the blends...