Honestly, we didn’t plan to be able to do that, but with some careful experimentation we figured out settings to make it possible with Proofgrade hard maple & walnut. Likely can do it with other materials too. The secret is going slow and removing a wide area of material on multiple passes so the lower-focused lens can do its trick.
It is 1/2".
Going thicker than 1/4" is very slow, so I wouldn’t plan on doing it regularly.
The slope is, if my recollections of trigonometry serve, <2 degrees.