Some data points for LAX-HKG. CX 881 never opened any additional Z space and eventually went F0 about T-36. Was F3 at the Sunday/14 day window. CX 883 (which had been F1 for the longest time) all of a sudden went F3 Z2 so I paid a change fee and immediately was able to confirm two of those for us.
Our return HKG-ORD was F5 and cleared the waitlist at the Sunday/14 day window. Waitlist notified me via SMS and email simultaneously and the deadline to ticket was the same as the waitlist expiration date/time so I actually had over a week to finalize the ticketing.
Tip for those that waitlist a RT upgrade, make sure you readd your return leg to the waitlist when the RT waitlist expires. That is not automatic although I was able to do it online painlessly.
Thanks to those that provided some guidance.