Well, after much work with a bobcat and auger the base of the pier along with 9 footings, all over 1m deep into the ground has been sunk. There will be plenty more concrete to come. The concrete that was used was 32MPa. The plinth for the pier will be 1200mm deep and 600mm diameter, reinforced with L shaped rebar. The tall poles, 100mm steel square beams will be cut to size.
I decided on just one pier. I could have gone for two but this would have caused issues with the minimum angles to the horizon, and possible clashing if I ever get a really long scope.
https://imgur.com/a/E8H9qwY