I'd love to see a tutorial or at least a timelapse of you working on this. I have been trying to do something similar for quite a while now, haven't quite nailed the separation between fine details and lose strokes.
I've been meaning to; I'll do one next time I do a watercolor. I start with the detailed bits, always the eyes first, then nose then mouth, and as I move away from those points I get loose. I probably spent an hour and some changed on the detailed bits...and like ten minutes on the rest.