As someone who flies a lot of Polaris flights on all aircraft types, I can help make this an easy choice:

1) It’s very hard to tell the difference between the Polaris seats on any aircraft (except the 757, obviously). Yes, some are more narrow than others, even on the same airplane. But if you’re flying out of your way for an inch of width, you’re flying out of your way….

2) Choose the flight with best schedule, regardless of airplane. I like the evening SFO-HKG flight. You sleep overnight and you land in the early morning. This practically eliminates jet lag.

3) If there is still a tie, then choose the connection at the airport that is least problematic. In this case, LAX (as SFO is prone to weather-related delays far more than LAX).