Unlike the head and torso, the silicone will be brushed in the arms and legs and then filled with rigid expanding foam. Here's a photo of the leg mould sections after the silicone had been applied. I imbedded strips of material into the surface of the thickened layer of silicone so this will bond to the foam.
I did the same for the arm moulds apart from also adding in a piece of thick armature wire, also wrapped in material, attached to some thinner armature wire for each finger. These wires fitted into the channels in the moulds' flanges. I also placed these thin wires into the toes of the feet as well before attaching them to the leg mould. This will mean I'll be able to adjust the position of the fingers/toes, it will also make them easier to paint evenly.
I have to wait until I have access to the workshop at uni in order to cast the foam into these moulds - I'm only able to do small urethane castings in my kitchen because of the lack of extraction!