I've done it from the Gold Coast Seaway and so have plenty of others. Not sure where your home base is but I wouldn't sail from Brisbane down to Coffs just to get a better angle to New Cal. As far as the weather goes I paid Bob McD about $60 to get his advice, but used Predict Wind to do my own weather routing.
Yep, I've heard the Sydney low story but basically you just get one type of weather for the time of the year you decide to go and the wind comes from all point of the compass (changing anti-clockwise) about every 7 days. I just waited till the wind was coming through NW to W and made my departure early in the morning. The wind then moved through to the SW then South then SE and so on. While the wind had mostly South in it, I used this to take me in an easterly direction probably bring me close the the Coffs-New Cal rhumb line before turning the boat for New Cal.
Point of interest: Did you know that your chart plotters will actually take you on the "Great Circle Course" and not the rumb line. The course heading changes as you get close to your destination.
Now the weather is the weather, it has many variations, so once your off the coast, you just make do with what you get. It's not a long trip to New Cal and the most you'll ever be is about 3 days from land.
I had planned to leave around May but didn't head off till the start of June. I only stayed in New Cal for 3 weeks before heading off to Vanuatu. And didn't return to New Cal till September. September is a hell of a lot nicer time to be there then May or June. In September/October we snorkelled nearly every day and the water was still a bit cold. It was a lot warmer up in Vanuatu. There was still bit of rain around and strong Southeasterly in June but they had eased a lot in September/October.
Sailing in company sounds good but doesn't really work out. In about half a day you're out of sight of each other and won't catch up till you get to the pub in New Cal (be it a Tapas bar beside the marina). But it is nice to be able to discuss upcoming weather patterns with someone doing the same trip.
Is well worth the effort going to New Cal as it is very nice cruising grounds with heaps of safe anchorages and handy cays and Islands.
Enjoy yourself
