What can be done to increase the chances of a GPU clearing when waitlisting is the only way? I am hoping to clear a GPU for the notoriously hard to clear SFO-SIN route.

Is there any way I can increase my odds if I am flexible with scheduling? Like flying off on a Tuesday? Or selecting flights that have more unassigned business class seats available? Choosing a day where more discount business class seats are available in fares D or Z etc? Any anecdotal experience or evidence would be greatly appreciated.

I know I could try flying through ORD-HKG-SIN and have a much higher chance of clearing a GPU. Would be a great chance to try the new Polaris Lounge as well. But I would rather avoid having to sit in the pmUA 2-4-2 configuration.

Thanks in advance for any input!