I have been through Coffs Harbour control area at least 100 times, never had anything but polite and courteous controllers happy to do anything they could.
Probably 10 of these transits were in a 50 knot 2 stroke ultralight aircraft.....
Just tell them what you are flying, where you are, what you want to do and where you are going. They will lead you step-by-step through the entire transit knowing that it is much safer for you to pass on by them to go inland. Many other times I transited in much faster aircraft but with the same hospitality expressed including a couple of times strong recommendations from the tower do not continue, land and have a coffee for a few hours break and wait for the weather to clear.
I adamantly say that their local knowledge and advice saved my life once when I wanted to push on thinking I knew better and they told me you will only get a few minutes past the airport and made a wall of water and they were right. You cannot beat local knowledge (and a weather radar before we had them on iPads).
I am happy to tell anyone this, no matter how little experience you have, there is nothing wrong or to be scared of contacting these guys, they are more than happy to help you at any time.