There are two options with the head,
It may be strong enough, to endure use, but with it being slightly small on its collard, it may be an issue?
The other option was to split the vertical pole and have two parts that move. clamped over the upper with a much larger collard area.

Rotation - Electronics 

I am having a hard time with considering the pack with them, it is simply because the movement can be more than 180 degrees. this would require a double arm ratchet movement, which also has to be strong enough to cope with wind. so it has to have moving power and stopping power.

Without this, the option is simply a pinch bolt that secures the rotation. this would be a friction part, but have considered adding bearings to make this more easy to move.

The Arms.
One of the more complex maths areas, as the weight and load has to be accounted for. 
Dropping the "face" for snow loads, opens up more problems for wind loads. as well as this you have a starting point of 3.4 meter full span, or half this on the pivot point. *1.65meters.

C channel (uni strut) I feel is too weak even at 41mm. Box would be more idea, and rails we have had a limit of 1.2 meters which falls a little short.

Well whats your thoughts?