After making the tool that will form the trim's profile, I made a jig that will hold the clay in place, as well as form the back corner:
And a picture of the forming tool IN the jig (this should clear up any fog):
The first trial run:
After letting it dry out a few days, it is firm enough to handle but still slightly wet that modifications can still be easily made. This is same piece on my counter. This practice piece is fairly rough and the final pieces should turn out much smoother as I will put more time into it.
But it works!