G'Day Seaya and welcome aboard CF.
Ann and I have made the trip from Oz to Vanuatu/New Cas a dozen or more times. We've left from
Sydney, Coffs, Southport,
Brisbane and Bundy so far, and each has some useful feature. Our trips have been in July, August and early September, mostly in August as you are suggesting for yourself.
Now, you must know that you can't leave from Pt Stephens, for it is not a
Customs port of entry/departure. You will need to depart from one of these official
ports. We have found that Southport has the best combination of location, convenience and easy departure, and that is what we recommend, especially for first timers. Our scheme is to be fully prepared, watered and fueled, and having notified
Customs of our intentions in advance. We then wait for an
East Coast low to develop down near
Sydney. This will provide a break in the SE trades with some W'ly flow for a day or three, and make an easy offing for you. We get as much Easting in as possible while that flow persists, and then, as the
wind backs toward the E, we can usually fetch Passe Boularie (if going in to New Cal) or go around Torch Bank at the south end of the South
lagoon and make the turn up toward Efate... usually without any beating involved.
Of course, the Covid situation may have considerable influence on your decisions. For now, NC is definitely closed, and likely
Vanuatu too. What the future holds is quite unknown, and you should bear that in mind.
I'd be happy to answer more specific questions...
JIm