Thank you everyone for all the great advice.

card1953 - I had not even thought about the 15K upgrade option, this could be my best last resort rather than using the VIP.

LLZ - I have the availability tool, only problem is everytime I try to use it I seem to have missed the window of time it is up. Nevertheless, I have checked via the Amex travel site and both AA72 & AA296 are showing F7/A7. Seatmaps on AA show 12 open seats in F for AA72 and 19 for AA296. While they don't necessarily mean anything I would feel better if I were on AA296 as far as availability goes. Unfortunately I cannot change the flight - I was lucky to snag a $434 fare HNL-EWR via ORD. This was great luck on my part as I'm flying to HNL from SYD (also on a very cheap QF fare). Originally my fare for the AA sectors was about $550.

Based on everyone's input I will track the F/A availability between now and my 100 hour window. If it decreases significantly I will try for a 15K upgrade. Otherwise I will hope that the X upgrade clears at the 100 hour mark and if not try for a 15K upgrade before the 72 hour mark.