While trying to optimize my raw files I learned a few things (with some help from Mike) that might be useful. I recently got a new Nikon Z6, which can produce really good jpegs, and didn't think my raw files were even close in quality. I suspect the best raw settings will depend on many things, the subject matter, the antialiasing filter, the sensor and probably the lenses used, not to mention personal preference.

First, I use the image examiner to see what the effect of changes is. When you rebuild the thumbs, it takes a while before the progress indicator at the top of the screen finishes and you hear the second clicks. About 12 seconds for a single thumb in my case, but it may vary a lot, depending on settings and the speed of the machine. I mention this because if you start the image examiner before the rebuild is done, you won't see the final correct result. Took me a while to realize that.

Changing the raw settings doesn't clear any raw refinements or filters (I think), so it's best to delete those- right click on the thumb for the menu and do both.

My subject matter tends to be technical. Brushed aluminum, black anodized aluminum, text and plastics, usually without much color. Smart color works great on colored stuff (duh!) but can be detrimental on my sorts of subjects, leaving a slight mottle in the noise pattern. I sometimes have to print very large, so the quality of any visible noise is important. I also have editors who like to crop rather than asking for a closer shot.

My images are already quite sharp and only minimal sharpening is needed. More than that enhances noise and can look unnatural. Noise reduction is very personal and you just have to experiment. In general I prefer sharp edges and some noise, as opposed to a softer look. When I did film, I liked my grain sharp, so it makes sense, but you may have a very different opinion.

OK, so what did I end up with? DFS at 1 & 175. Put the slider below right under the 1 in 175. Noise reduction off. Special noise reduction off. Camera specific settings on. Smart exposure on. Auto fill on. Auto black level on. Smart color off. The rest as you prefer. Remember, you can turn on smart color in raw refine if needed. Ditto some noise reduction.

Those settings apply to my particular situation with the Z6. My main point is you have to experiment as the defaults may not be optimal for you. Hopefully what I've said is close to truth, but hopefully Mike and Fred will jump in and correct what isn't or maybe add to the knowledge base.