i'm 3/3 EWR >>> HKG and 3/3 HKG >>> EWR, from Wednesday, Thursday and Friday outbound and Sunday, Monday, and Tuesday inbound. 2x during Winter holiday season and 1x during June. I've usually cleared at least one leg at booking, with others clearing about a week to 3 days out. The last one on a Friday departure was the hairiest, with calling in after noticing R showing availability and me +1 still sitting on the WL at T-4 w/ under 10 seats not reserved on the seat map.

i already booked another R/T in June and cleared both ways at booking.

Fridays + Saturday outbound are def tougher for UGs so choose midweek days if you have flexibility.

i'm burning miles + copay for the GF flying back to HKG in early April, and the cabin shows a bit over ~20 pct reserved at the moment.

w/ out flying the ORD routes, from looking at seat maps it seems the ex-ORD route seems to fill up in C faster, perhaps b/c there was just a bigger sUA flyer base. not sure if there's any validity to that of course.