I feel like if I worked with a clay that hardened on its own I'd feel more rushed to get it done.

When I use super sculpey I make things in sections on top of a wire armature instead of all at once. That's a pain in the ass to try. I'll make the torso of a pony and all four legs, bake it, make the neck and head, bake it, tail and ears.. bake it.. You get the idea.