You can only extend 30 days, your airline might require you have a means of exit within 30 days i.e exit flight, bank statements and regular transfers to your Thai account of over 40k. Probably easier to apply for a 90 day non-o in Australia then extend once in Thai . It'll make opening a Thai bank easy and then getting your money transfers in etc as proof.
AirAsia refused me with a bus ticket years ago from Singapore to Thailand. After a lot of arguing and showing them links like yours they eventually let me on, but what a headache
like this but some airlines will need proof you're leaving within 30 days so you'll need a throw away flight for this. Probably easier and cheaper to get a tourist visa if you have the time. Though there's talk of visa prices increasing soon