Is there a rule of thumb when the different classes are released?

I'm looking to book a trip to Australia for next year. So far for the dates that I want to go, the lowest outabound available is T class and the lowest inbound is W class. The flights are 10 (or 11) month away. For the ones that are 11 months away the tickets have not been released yet.
I would like to pick up L, K, G, N since they would probably be cheaper.

Thanks!