The armature is typically built to mimic skeleton of the sculpt. Using a thicker armature wire for the skeleton then wrapping floral wire around that to give the clay something to hold on to and prevent it from slipping off the armature. You can put tin foil over that to bulk up the skeleton then wrap thin floral wire around the tin foil to secure it to the armature.
you can see a pic at the following link to give you an idea of what I mean.
https://www.csmoorestudio.com/v/vspfiles/V4_Backup/blog/2008_05_04_archive.html
hope that helps
Thank you, will definitely try that out, but I wonder if there is a guide to show how to sculpt the neck/head to make it fit a Hot Toys body?