And... it's done:
Some of the simplest looking areas were actually quite fussy to do- for example, the grass. The foreground grass is darker, with thinner and narrower pieces. As the grass goes toward the horizon, the pieces got lighter, thicker and wider. And always, the curve shape had to be evaluated and matched for even grout lines.
The horses were relatively simple in comparison. I made paper templates from copys of photographs enlarged/reduced to the correct scale.
Grouted in two colors- white for the sky and tea green for the remainder. The tea green had the desired effect of blending the background and fracturing the focal objects so they are more prominent.