craftgrrl | Plaster of Paris? In the Oven?

Hello! Does anyone have any experience with using anything other than porcelain slip in plaster-of-paris molds? Full details behind the cut, since this is a specialized question.

I've made my mold, and (with no access to a kiln) I've been considering possible mediums to cast my actual pieces in (if it's relevant, they're dollhouse-doll pieces). I'd really prefer to use a slip to get the fine detail and allow for hollow pieces, but the only air-drying slips I've come across are flumo (I've only found one expensive source) and Liquache (haven't been able to find a source). I've been considering liquid sculpey or really soft regular sculpey--but of course that would necessitate putting the whole mold in the oven to bake it. Logically it doesn't sound like a problem, but after searching the Internet and finding absolutely no information about it I'm nervous. Will the plaster crumble? Is this a really bad idea? Can anyone give me the benefit of their experience, please?

Thank you very much~