Thank everyone for posting their tips or anecdotal evidence. I understand there must be a lot of people who are frustrated with their experiences of not getting their GPU's cleared. It's a system that isn't very transparent and involves putting in more money and sometimes not getting anything in return. So the complaints are warranted.

In the meantime, I have gone with the confirmed ORD-SIN flight upgrade on the pmUA 777 2-4-2. But will gamble with my chances from SIN-SFO. And taking the tips of looking for open R space periodically, looking at flight load changes for similar departure days, and praying to the GPU gods but keeping expectations low. And maybe in the future buy up to a higher fare than W like V or Q.

Currently the return flight has many unassigned businessfirst seats, more than half empty. But expect them to fill up as the date gets closer.

Any more anecdotal evidence, tips, or strategies would be appreciated and helpful for future GPU waitlist gamblers.