i agree with most of that, except the roosting half up ridges.

From my experience, where they roost depends almost entirely on wind.
If you have a windy evening-night, they will roost at or towards the bottoms of valleys/ridges, and in calm evenings they will tend toward the mid-upper trees on the ridges.

Which way they tend to fly down also seems to depend on wind, windier days they will spend in the relative calm of creek bottoms, and nicer days are often spent in more open areas.

Mat