I guess....
https://www.cbs.org.au/Native_Shows/bons ... 0large.jpg
That is an example I have always liked of a close attempt to getting the 'bones' right for a good start to styling it in its natural growth formation.
I am not saying the branching isn't 'casuarina' styled on yours, as I can see you have put a lot of effort into that, as with them in the wild, you will always see branches gradually going up, or branches gradually going down and more often than not, you will see both examples on the same tree. It is more to do with the upper half of your tree.
I think it is also the tapering of the trunk on this one, and the way it has the 3 point metric of a traditional oriental styled tree. Again, I love it for what it is Steven.
It doesn't scream out to me 'natural looking' Australian casuarina for the above reasons. But having said that, in the wild you will definitely see a trunk going off at a sharp angle and then gradually growing upwards. But normally you wouldn't see such 'good for bonsai' taper on them in the wild though, which can make this species

not very suitable for shohin for this reason. Generally wild trunks are quite long and without dramatic tapering like yours. I hope this makes sense, and you don't think I'm picking on you. I love your passion for natives, and these are just my thoughts.
If you look at the 'inspiration for bonsai' threads you posted many years ago about casuarina in the wild, it is the trunk (the backbone) of this species that should be focused on mainly for casuarina in my opinion, including the upper half of the tree as the trunk can often form multi trunks and spreads upwards on mature species.
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From my experience, most often in casuarina, main branches will develop 'multi trunks' as you go up the trunk, and you don't get that oriental 'one main trunk and branches going off to create the whole tapering of a triangle of branching' formation style. Generally the upper half is more of an elongated cone, rather than a triangle. One very distinguishing characteristic of casuarina is main branches can grow almost parallel with the trunk upwards and THEN, they curve down or up for the straggly and ragged growth that you have depicted so well in all your branches.
The plucking you have done is perfect, and creates the illusion of size perfectly.
If it were mine, there is really nothing I would change with the lower half, it is awesome, I would be changing the upper half. But again, this is just my thoughts Steven. What you have done for Casuarina bonsai in Australia I

you.
*EDITED to include the very helpful threads Steven posted on inspiration from nature Casuarina*