Fly hook size will come down to the patterns your tying and the species your targeting ??? For most bass and native patterns in QLD impoundments you'll only need size 4 , 1 and 1/0 sizes. The style of hook you use will also determine what size to use - as not all brands size their hooks the same.
Let us know what patterns your looking at tying and species your tageting and we can be more spceific.
Regards Scotto
The Alpine Angler