Thanks for the comments (at least the ones that were at least a little on topic ) here's a quick summary.

* Stong consensus that SFO provides a slightly better UA experience (RCC and crew) and shorter trip. Suggestion that LAX may be preferable inbound for INS/TSA hasslements.

* Stong consensus that upgrade probabilities are significantly better out of LAX. (Not helpful to me, as the MH fare is considerably higher than Q. I might pay it out of my pocket for a confirmed upgrade, but not for an upgrade lottery ticket.)

* Presumably buy up also higher probability to-from LAX, any suggestion other than to ask at checkin/gate?

* Soft product on SQ SFO-HKG recommended, but E+ definitely trumps.

* No comments one way or the other about flying via NRT?

* I should pay more attention so that I don't have to be coherent on three contintents in three weeks.

I'm planning to schedule for LAX on the return; haven't quite decided between LAX and SFO on the outbound. There look to be a couple exit row seats available as well.

Thanks for the comments!