I have gold status from a promotion and only flew AA once 5 years ago.
Flew from DEN-LAX-HKG (Wednesday. Thrusday 12 am for LAX-HKG flight) and HKG-LAX-DEN(Tuesday)
Requested upgrade using miles and copay 2 weeks prior to first flight because I heard it cleared pretty easy(I had to transfer points otherwise I would have requested earlier).

For DEN to LAX and LAX to HKG, nothing cleared but I was 2nd on the waitlist for LAX-HKG. Only seats open was 2 first class and 2 other people 5 and 6th on the list got upgraded to it. I probably would have gotten upgraded if I requested earlier than 2 weeks before the flight.
For HKG-LAX and LAX-DEN both cleared about 2 weeks before the flight(Requested about 3 weeks before the flight). There were still 7/8 first class seats open when I checked the day before with 0 business class seat. I didn't check if anybody got upgraded.