These sculptures are called Quick-Sculpts, due to the fact that I was given only three hours to complete each piece. This was a concept, created by Cindy Jackson, similar to the idea of the Quick-Sketch practice often used in life drawing.
Cindy had an ingenious idea of how to cut sculpting time in half. By pre-casting wax figures with armatures, the artist was given more time to work on capturing the pose and lay in the fine details without wasting a huge amount of time in building the basic form.
I would start with a basic human form of clay including armature so that all my time could be spent on finding a likeness of the model's pose, discovering unique proportions, and eventually getting to some of the finer details (if time allowed).