Thanks @jgonzalez . UMotion looks extremely interesting – hadn’t heard of it. With the Pro version I probably could do everything I’m attempting completely inside Unity. Probably a more streamlined process, although I am more familiar with Blender. In my case I was a little lucky, because I could just splice together ranges of standard clips and get pretty close.
I tried ranging/chaining standard clips and fiddling with transitions (the normal way in a Controller), and I can get in the neighborhood, but not as precisely or smoothly as I like. The required motions are really tight.
I’ve used add/sync layers somewhat in the past for adjustment. I completed the blend tree training but haven’t tried constructing anything that way yet.