There are batteries included as part of this project. So I don't think time really matters.
If this project is viable, then it'll probably be more viable to have a massive solar farm coming from India, where the timezone shift is in the correct direction, and it would outcompete Australia.
So either way you need batteries, and all the problems they bring. Just about "how many".
Edit: I'd also like to add that for something cheap and mass manufactured that we shouldn't concern ourselves with, we sure don't have a lot of it on a grid that already delivers some of the most expensive power in the world. ie one that should be able to afford it a lot more than others