Not so...your dollar and mine are less than 2 cents apart, and shipping to Australia from Canada, UK or the USA is actually very inexpensive....I know, I have sold a lot on eBay to rural folk in Aus.
I do not buy anything from overseas ever, i buy Australian, support my own country. And not all rural areas are the same. Posties do not even deliver where i am *L* Again regardless of cost etc, i just plain do NOT want to do pressurized CO2!!
Not sure of availability down there, but I understand that Ocean Spray juice bottles are fantastic....heavier, with a wider mouth, larger bottoms (to prevent tipping), and overall more rugged.
Coke bottles will do the job perfectly, they are designed to hold built up pressure and sit quite well.
I do accept that...just trying to throw out some ideas and advice...four decades and over 2500 aquaria has given me a lot to share.
And as i said i read your ideas, but they do not match mine. You are not the only one with a good amount of experience. Advice can be given, but please respectfully do not continue to badger when the person has over and over said they are not interested in doing something your way

I dont want a tank i have to monitor constantly or trim constantly because of wild CO2 growth. I like my low tech low maintenance tanks, i wanna enjoy them not constatly have my hands in them adjusting *L*
Very nice. It is pleasant to see someone doing angels well....they seem to have fallen out of top popularity here in North America in the past 20 years.
Angels are still quite popular here.
It is essential in some degree, but it is not a necessity to have via a delivery system. I have done both, and simply find that using a pressurised system permits you to do a lot more with the tank, and I hate being limited.

I am not quite AGA or ADA material yet, but I am working towards it.
I like limits, it makes you try new stuff to try to push the boundries of them further than others think they can be pushed.
Plants need CO2 definately, what i meant by the be all end all is the deliberate addition of CO2.
The tanks above are proof of that fact. I have had many tell me it is impossible, that those tanks had to have had CO2 added, calling me a liar in essence. Why, because the die hard 'you must have CO2 to have a decent tank' people are stuck in their thinking.
Again, respectfully, if you like all your high end gadgets, well and good. I am more than happy to play in the low tech part of the aquarium hobby.
As stated if i feel the tank needs CO2 it will be DIY or nothing at all.