Some interest has been shown in our plan to get back to Perth, so here are two photos taken from World Cruising Routes by Jimmy Cornell, who is much better at these things than myself.
They show the progression of a band of variable winds northwards over the Bight. The band is coloured blue/green in the photos, you can see how into April, it is replaced by westerlies. Hence our plan to cross the Bight in February/March and lessen the risk of having to bash into the westerlies for the whole trip. I think it is a feasible option, and who am I to disagree with Mr Cornell?