Bonecradle & Realnorth: some great tips you gave me there! I’ll certainly include them in my next scupting session. It’s interesting to see you both are telling me to push it more, make the formes more extreme and defined. My last couple of changes were very subtle one (with very low intensity settings), but if I want any striking resemblance I’ll have to be more bold. Gonna try it all, thanks! 
And Realnorth: this started out with a couple of ZSpheres. Big one for the head, one for the chin, and four for the extravagant ears. I’m not very handy with ZSpheres, so I left it at that and didn’t make eyesockets or mouths or noses. I did that all later after I converted the ZSpheres into an adaptive skin. Fun thing with Zbrush: you could do this with a Sphere3D as well, or with a cube, or with an imported base mesh. Or even with the demohead that comes with Zbrush3. More ways to Rome. 
AngelJ: thanks for the pat on the back. Yesterday it seemed to me I would never get there. My eyes have never looked at things like this, and the curves of a face are very complex and sometimes subtle. It’s fascinating learning a bit about it by doing this. The feedback the forum users give me is a great teacher. 