Thanks.
I followed Kris Kosta technique using ‘Plane3D’ tool, but first I made projections with huge parts of the frontal and lateral view photos, as I had all those pretty wrinkles there.
Before exporting the brushes from Photoshop I removed strong shadows with ‘Dodge’ tool, but not removed them completly.
I exported as well smaller brushes, ‘neutral ones’, and ones with some small details, to fill the rest of the skin and to blend unions and imperfections of the first, ‘bigger’ projections.
My model was still in the 3rd level of subdivision when I had it textured completely.
Then I subdivided it more and I used the texture as a reference, turning it on and off, to sculpt all wrinkles and make it fit together with what I had painted there, but without being perfect. I just played around to see what happens. 
The initial low-polygon head modelling was a longer process, as I was improving it many times recently, but the ZBrush session was rather short.
I’m going to improve it if someone help me to find errors.
Cheers.