Good morining 
Thx for your answers, Julian and Lukas!
Makes sense.
We tried to avoid movements by putting the backhead agains the wall.
I try to find a solution to kinda fix the head even more and do quicker photos.
Yes Lukas. the model is more important since we gonna change the look completly, but of course based on the original texture.
Even the model I can edit easily in Mudbox - but as better the result, as less scuplting and time 
Thx again, I gonna try again with quicker photos and less movement of the model.
Markus