Some are full moulds , some just faces . I actually just use the face part myself , I fashion a kinda head shaped ball with a bit of a neck and push it into the mould . Mostly I cover the back with hair and I find this way I don't have to work so hard to remove the mould line that forms where the two halves meet.
I have seen few molds in squires, need to get some pennies, do you coat the icing in cornfloutr before you put it in? I used to make soaps and have a few wee silicone molds and i tried to push in fondant into 1 easy mold just a smiley face one and tried to peel it off, came to bits lol i gather you are meant to leave it in mold to harden up? xxx