If you're going to invade, then you need to sieze and hold ground. light forces can do that for maybe 2-4 days while they wait for larger elements to kick in.
The logistics tail alone would mean that heavy forces would have to be in transit within 3 days of the light prelim invasion force starting out.
I'd be less than enthusiastic to be an Indon general trying to traverse JORN managed battlespace, as well as having to deal with subs coming from the west coast.
RAAF would have a field day picking off the invaders, they would be locked onto Tassie with nowhere to go and with only 2 airports to utilise. That makes targetting a dream for the defender. Similarly, trying to offload an invasion force in deep water means two spots as well.
I'd like to see any invader try and manage Bass Strait without any local knowledge.....
It would be a turkey shoot....
Logistics and momentum is the key - extended maritime invasion lines just don't work (esp once steam took over from sail). Look at history and see how they're all relatively short. Or look at Tawian. Thats 90km's and thats a nightmare scenario as it requires considerable overmatch. A 4-5000km invasion journey would be an unmitigated disaster. They can be harassed from air for 3/4's of the trip, they can be harassed by subs at a higher rate, and they would get picked off at changeover points. All of their power has to be organic, they cannot escalate as they have finite resources and they cannot afford to get into a protracted contact as again their munitions are restricted as the bulk of the weaponry is designed to be used for sieze and hold. So there will be limited weaponry at an organic level to defend the fleet from land based and long range defenders who can overwatch and re-arm from points outside the reach of the attackers.
You're right. You should be the enemy general.