Thanks, Onslow.  In a nutshell, much comes down to hands on experience and gut feelings in a hurried shot and precise balance in a set-up needing it.   I agree, auto on raw helps a lot but still is sometimes off.  The problem I have is reference objects of a color I actually "know" is right, as you mentioned about the clutter of color in a butterfly shot, shot essentially on the fly.

For images at work, techinical sorts of things, I did a lot of work on wb for reference photos but learned the printed ones were always in grayscale!  That changed the procedure to one much more simple for printed images at work.              Tom.