Using AAdvantage miles to fly Mrs. BdaDiver and yours truly to Bali next July on an All-Airline Award.

Tickets are issued and we're good to go. Again,
I was not able to obtain seat assignments on the four CX flights as the agent said that she received a message from CX that it is too early for CX to release seats.

Can anyone tell me how far in advance we can reserve the seats? We want to ensure that we get seats 1A and 1K on the trans-pacific flights from SFO to HKG.
Thanks in advance for helping.