AC generally has pretty good availability in Economy at the 80K redemption rate on the SYD flight to/from YVR; it looks like this is the case for an Australia-bound early July departure. Mid-July returns look to have less availability, but still some via SFO (UA) and ICN (OZ).

I see decent availability for UA saver F around that time if you are willing to part with 160K miles for it.