Again following the advice of Animation Toolkit's seminar at Manchester Animation Festival, and based upon the relative success of my stag puppet, I chose to build up the bodies of my characters using a car cleaning sponge. It provides a good density and is easy to sculpt. However, I found this process to be quite time consuming as I was wary of making to big or drastic a cut, as it would be difficult to build back up any areas which were accidentally cut away.
I built the bodies up bit by bit, keeping joins exposed where possible in case they were to come loose with repeat handling and manipulation.