Yes it is shallow going inside past Fraser, it is well marked - you just have to get the tides right... no big deal.
I don't have my own boat yet but have crewed extensively up and down Oz east coast
including lots of GBR on lots of different boats. Also heaps in Louisiades PNG, Perth to Melbourne, a lap of Tassie and Hobart to Sydney
All boats I have sailed on (except cats) have had 1.8 meter draft or very close to it which I believe is a good balance between performance and shallow water access.
I would suggest a bolt on fin keel
is not nessasarily as ideal for cruising as a three quarter encapsulated keel
or similar if you hit things like coral reefs
. Fin keels more likely to sustain damage in a hard grounding or hitting reef. A three quarter keel encapsulated is pretty tough as I have experienced some pretty good hits with such keels with no damage other than a chunk of missing f.glass, laughed at by the owner.
Also be aware of rudder depth
, if your rudder
is a big fin type like I have seen on the new hunter
50ft which is the same depth
as the keel this might be a big issue when trying to reverse out of a grounding in mud. If it catches in the mud you could bend it pretty good.
Personally I don't want to be in big ocean conditions (which you can get on the east coast) with any kind of shallow draft centerboard
If you want shallow draft
get a cat or a tri. Otherwise get a proper keel about 1.8 meters deep.
Your depth gauge and charts
will help you keep away from the shallow stuff and a sharp eye.