I have been thinking it over and I think I messed up my laser depth cut tests earlier. I need to set the focus height for the optimal first line cut before attempting to test if lowering the laser has any benefit. I'm fairly certain that I was starting from a lower depth before and there may not have been any benefit to going even lower after that.
In addition I want to run a test where I move the laser sideways to cut a wider kerf before attempting to cut deeper. I suspect running two or three side by side cuts combined with two or three depths may be enough to get through much thicker pieces of wood.
Finally I need to run some tests to see what the optimal focus height is for engraving. Is it really true that engraving should be focused at the surface while cutting should be focused deeper? My tests so far don't seem to show this, but they have been far from scientific up till now. I need to come up with a way to measure the spot size (or line size) accurately so we can try to find the smallest spot with more precision than the ramp test. Maybe it is time to dig out the microscope.