Blogger won't let me edit my last post at the moment, so here are the additions I wanted to make. If I think of any other things I want to add, I'll put them in this post (assuming Blogger lets me).
There's an "Undo" button at the bottom-center of the Spore CC. It seems to undo an unlimited series of actions. So if you mess up in any way or something doesn't go as planned, just undo it.
Keep in mind while you're messing with the torso that the game considers one end to be the front even without anything on it. Which end it considers the front determines which way feet and hands will face, and which direction movement goes.
The CC does have bugs (no pun intended). Fins and other "details" often reset to an unwanted orientation whenever you mess with the torso. Non-detail parts might do this too, but I can't remember. This bug is annoying, but you can remove and replace the troublesome parts with little time or difficulty once you're finished adjusting other things.