if anybody could possibly suggest a mixture for my little bonsai, it'd be so very helpful.
For an Aussie I would suggest the following,
Ray Nesci mix = $11 for 15 litres
(if you don't want to mix your own, though I do recommend you add a little chopped sphagnum to it)
If you mix your own
Diatomite and Zeolite = $35 for 60 litres
(I would suggest Maidenwell Diatomite brand as it is much firmer and will last longer without breaking down. https://maidenwelldiatomite.com )
Akadama = $16 for 12 litres
( not necessary, but your Juni will respond and develope quicker IMO .. its an ingredient that will fine tune it)
Aggregate ( choose any stone that is a 1/4 to 3/8 grain size with sharp edges...if you can get lava that would be ideal)
(New Zealand white / Angel Moss if you can get it. Chop this up and added it to your mix, your Juni will LOVE IT!)
No one here can tell you what the best proportion or ratios to use for your soil mix. We don't know what your climate is and for that matter what your micro climate is. Its best to seek out someone else in your area that grows bonsai and see what proportions they use...Check for local clubs, or Associations in your area.
I know this was not as specific as you wanted...but its the best advise since we don't grow there... You have the components, just a tad more research and you'll have your answer.