Start with equal size parts of molding putty--a bit larger volume than your piece...looking at this these are on the large side!
Form the mixed putty around the original--this is a Bisque Doll Body.
Stand up and and pinch down the FRONT of the original. This helps you keep track of the front when you need to cut it open.
Leave a small opening at the top to pour in the resin and make sure you have a solid base so it won't tip over while the resin is drying. Allow the mold to dry for at least half an hour, then cut down one side with a jeweler's saw.
Use duct tape and wrap tightly around and overlap the tape as it won't stick to the silicone mold, it has to stick duct tape to duct tape. Not pretty, but effective!