Millings when exposed to hot sun will re-bind and give U a 'near asphalt' drive, not like true asphalt bet great for a private drive.
On slopes , unlike crushed stone, millings don't wash away being kinda glued together.
For a top notch job a roller compactor is the way to go.
Good news is re-cycled or millings is cheaper to buy than crushed.
I did my hilly drive 20 years ago with re-cycles and it still works for me although it has many cracks in it now, the main thing being that I never need to grade as I did with gravel.