The best info I can get you is
this. It is a little tutorial from Recluse who is no longer active in the community. Her casts were good enough quality that Armothe has used some of her work on the miniquins in the store. Another source that is active is
Confuzzled Apples on Flickr. She has been working on hair and armor and her work has improved with her experience.
Billy Riener is another person that is working hard at perfecting casting. Maybe check out their stuff or even contact them to get some better advice.