Book cover process: hand sketch, AI color studies, final paint

The steps:

1. Thumbnails by hand. Pencil on printer paper, about a dozen tiny compositions. The winner is a lone figure on a ridge with the city below, mostly because the title needed room at the top.
2. Cleaner sketch. I scanned the thumbnail, redrew it larger in my painting app, and fixed the figure's proportions, which were wrong in the thumbnail.
3. Color studies. I fed the sketch into an image tool a few times to see palettes: cold dawn, warm dusk, an orange-teal option that I disliked at once. I used these as a palette reference only and kept none of the pixels.
4. Final paint. Painted from scratch over the sketch, picking colors off the dusk study and ignoring the rest. Brushwork, edges and the cloak are all me.
5. Type. Title and author name set by the author in a separate layer, so the art can be swapped later.

What worked: the color studies saved me from committing to a bad palette after ten hours of painting. What I would change: I rushed the hands and the ridge line is too straight. Still, the author likes it.

Feedback welcome, especially on the value structure at thumbnail size, since that is how it will first be seen in a store listing. And has anyone sold a cover made this way where the buyer asked how it was made?