is there a built in height control?
Yes, maybe, no. 
@steve.lessard do a search on “thc” and you will see what I mean
There are a lot of posts on this topic. Some folks have it working, and share their YouTube videos. I believe @Andrew still has the concept on the drawing table too. As much as I thought THC would be needed, I’ve found after many projects/cuts, I didn’t need it at all.
It works depending on your expectations, I use it for most cuts if the material is uneven. Most people I’ve helped have it up and running but I have yet for it to be completely consistent. It does work a bit better on thicker material, like 12ga and up. Even with my own divided voltage board, settings and a good TH value capture, sometimes it will want to bob and it does affect cut quality.
I have a more invasive solution in the works but I’m not sure if it will be practical for most people to do.
