Four stages of tumor progression, updated

I posted an initial sketch for this illustration here on April 24th. One way I've been trying to continue to improve my work is to make more thumbnail sketches. It's a good way to find the best composition. But this time I may have overdone it. I just counted, and I apparently made no fewer than 24 sketches for this project. Obsess much? This is the first digital version, still in greyscale because I will have some direction in terms of the color palette.