Do Cribby's Lancelin Freewave course.
Last 2 years has been in late January.
4 days of coaching including video review.
You won't regret it! I did it in 2013 and after years of stagnation (30 years windsurfing on and off) made really significant progress.
www.guycribb.com/Search on seabreeze for videos and other reviews of this year's courses
or Simon Bornhoft also does a Lancelin course
www.windwise.net/ usually December
Staying at the same location as people on your course with wave options makes it the best bet in WA.
Saying that, the wind in WA has not been as consistent over recent years and you could still get skunked at either time of year so be prepared for lots of drills or light wind practise if Huey doesn't play fair.