I'll be getting a plug turned on a lathe for the whole section shortly, I really didn't want to go with half or quarter sections.
I thought of the heat gun route, and it's doable. However, I also had a crazy idea of getting some BBQ brickettes, laying them out, and having the plastic elevated over top.
I think the heat gun route would probally be best. Clamping the plastic to a frame and onto the form with the vacuum on and using the heat gun until I have the shape.
Thanks for the reply Mr. Badwrench, I appreciate it!