Thanks!
My biggest misunderstanding was thinking that the analog out on the controller was simply a standard DC output that was adjustable. Now I see that it is a pulsed output with the averaged DC voltage as the measured output.
So, if I wanted to control the temp, I could slow down the temp increase by lowering the duty cycle and speed it up by increasing the duty cycle. If I wanted to go from hot to cold (or vice versa), I would need to implement a H bridge. The code stays the same (for the most part), but i would need to switch polarity by closing the correct contacts on the H bridge. At least that is the idea, correct?