After my client had chosen his favorite pose, I added a base to my bust and began my polishing pass.
Lighting/Shading/Rendering
For my presentation I used a typical portrait light setup. A key light to cast shadows, a rim/back light and a simple fill light (Fig.17).

Fig. 17
From ZBrush's Standard Materials section, I chose the SkinShade4 material. I started to change the Specular and Cavity colors. My idea was to give the presentation a really soft look. Therefore I also lowered the Specular value and adjusted the Specular Curve. Fig.18 shows you the difference between the two materials.

Fig. 18
To render the final image I used ZBrush's Best Preview Render (BPR). As you can see in Fig.19, Shadows and AO were enabled, and Details had a value of 2. Under the BPR Filters I chose Filter/Glow with the blending mode set to Lighten, activated the Floor Grid, and increased the Rays and Res values.
Compositing
Compositing was done in Photoshop, where I combined the different layers with different blending modes (Fig.20).

Fig. 20
And here is the final result (Fig.21).

Fig. 21
I had finally delivered a design with which my client was happy!