As almost anything related with photography, there’s not a single, true answer to your question. It will depend on a few factors: your sensitivity to noise, if you will be downscaling the final image, the quality of the input raw image, the amount of processing you will be doing to that image, …
I have a tendency to think about Capture Sharpening (CS) as a tool to take the image to the best starting point for other tools. To me, it’s just as important as the correct demosaicing algorithm, the white balance, and choosing the right color profiles.
If you have a really nice sensor, with an outstanding lens, coupled with a perfect shooting technique, then you will need little to no sharpening applied to your images. On the contrary, if you fail on any of those points, then you will need to enhance your images.
In other apps workflows sometimes people talk about the need of pre-sharpening the images. There’s a lot of debate about that. In RT, with CS you will pre-sharpen your image. How much will depend on how much you will further develop it: the more you play with contrast (tone mapping, contrast by detail levels, wavelets, local contrast, …), the more you will see the artifacts introduced by CS with strong settings. In my workflow I tend to be gentle with CS settings, as it won’t be the only tool used.
As Thanatomanic said, most of the times I find myself lowering the radius and iterations from the auto-calculated values. They tend to give halos not really visible at 100% or lower zooms, but not desirable in my workflow (for focus stacking). Radius between 0.46 and 0.60 are usual. And iterations between 5 and 15 are usual, too. As you may guess, with those values the sharpening is not so WOW!, but it helps the other tools to better do their jobs.
On the contrary as Thanatomanic, I usually leave the auto-contrast threshold value as is, or maybe increase it a bit. The idea is to not sharpening noise, as in focus stacking it has a tendency to increase exponentially.
If your image will be downscaled…, well…, you absolutely need a post-resize sharpening, as almost any sharpness improvement you get with CS will be lost. The aid of CS to other tools of the processing will be there, yet. So even if I downscale my images, to me CS is a must, and should be almost always on.
As it is said somewhere, CS works better with the unsharp mask sharpening. In my experience I have used it with both US mask and RL deconvolution:
- with unsharp mask: I tend to use this method with a Hiraloam approach, that is, looking to enhance the perceived volume of the subject, as I have already played with contrast during the developing process, and the image already looks sharpened
- with RL deconvolution: in this case the image lacks a bit of crispness, so I use this method with a high threshold to enhance the most prominent details, while leaving alone the tiniest details (and remaining noise). Note in this case that this tool has a tendency to quickly generate halos
Hope this helps. But honestly, the better way to find your best workflow is by playing with your images.