So help me understand back scatter and side scatter...
How does this work and at what azimuth?
The pragmatic answer is, when you hear a station you want to work swing the beam to
peak the signal, whatever direction that happens to be.
The direction varies, depending on what paths are open at the moment and the relative
reflectivity of the surface of the Earth in that direction.
High power helps, too, as the reflection is usually rather lossy.
Imagine you have waves in the ocean with angled faces: a signal of the right frequency
arriving at the ideal angle would reflect off the face of the wave back the way it came
if it is at right angles to the wave (or at a different angle otherwise). Ideally the angles,
frequency, and wave height and spacing would all combine so that the reflections from
multiple waves are in phase over a reasonably large area.
If you are trying to work a station relatively close to you and the reflection zone is a thousand
miles out to sea, you may need to point the beam nearly 90 degrees to the desired path.
But there are other sorts of reflectors as well, and in some cases you might have to point
South to work North if there is a good reflector in that direction.
Expect signals to be weak.