@Gordon ********
You got limited choices,
You sure aren't gonna use tourist visas or free entry stamps because you'll get pulled aside and denied entry before too long on those
You COULD show 400K baht in a thai bank account for 2 months and go to the thai consulate in Savannakhet to get the year long multi-entry Non-O based on marriage when you're here.
OR
You email Sydney and see if they can sell the year/multi Non-O on a case by case basis. There were reports from other countries who are in the eVisa system where a consulate DID issue a year/multi non-O even though it's not a choice