The one caveat with black horses and that lovely golden sun, is it turns them *bay*. All that yellow just makes a black horse brown. It is the wildest thing.

The golden light will be ideal with the cremello, but, may be too warm for the blacks.

And yes, about 30min is all you have for the perfect light. It is a real balancing act with at liberty shots because that same light isn't as bright and slows your shutter down. Which is bad for moving shots.

For the friesians, I might try and do an early morning shoot as the light is beautiful, but more blue. And, it gets brighter vs lower. They would have to have the horses ready around 7:30 to 8am though.