A fixed part of my workflow has become the frequency separation filter. I mainly use it to do my final sharpening. I dislike doing this in RT because I don't have the tools to accurately control what I want sharpened and more important; what not.
This is my shot without final sharpening:
I then apply frequency separation at the absolute minimum; 0.1 and delete the low frequency layer. It then functions as a high-pass filter but suffers the same issue as unsharp mask; nasty fringing at high contrast areas:
In this case it is very visible at the feet. I simply fix that by erasing everything I don't want to sharpen or what suffers fringing. Some more tweaking and I'm done.
It works much better than trying to do this in RT or any other RAW editor. They're simply not equipped to do this decently.
The previews here suffer scaling issues; to see them without click the large versions.