What a lovely looking plot Phil, can I ask where that is? even approx? Looks like Yass way..?
Wow, so many options
....Oooooh, where to start??? I know you are thinking differently at this stage but I am certainly a dome man (I've built three now

), easy to setup (Slab or simple deck is all you need) no dew problems (I use no dew heaters on my AG12 Newt, only the three extractor fans at the back of the the OTA), wind is essentially a zero problem - sub arc sec guiding accuracy is possible even in high winds - living in the Yass/Murrumbateman area strong westerly winds are very common and before my dome many nights were basically written off due to wind.
Of course a roll off works very well for many too, so as I said, so many options - enjoy the planning and construction journey, great fun ahead
Mike