Johnston Original Art Dolls

Hello! I'm new to dollmaking, but have fallen in love with sculpting. I like the option of making a sculpted head and breastplate, but I'm finding so little information in the books I have on how to do the breastplate. I did see some references to a book by Bob McKinley, but it is out of print and far out of my current price range. I have every book written by Susanna Oroyan and several on sculpting. Do you create the armature first and then sculpt the breastplate over the top? Can the armature be put in the oven with the sculpted head and breast attached? Thank you!