Planning to a Quick Trip to China

I needed to make a quick 7 day trip to China in April and have a choice of using my AA, BA, UA, US, or DL miles.  After exploring my choices on using my Delta SkyPesos SkyMiles... the flight times and connections were pretty limited.  US airways does not allow changes on award travel for free and I have to pay a booking fee.  British Airways has a pretty expensive chart for long haul travel and also flying in Business or First Class in very expensive. 

That left me with AA and UA miles which both allows one way travel.  I needed to get to Guangzhou and both American's Partners of Cathay Pacific (CX) and Japan Airlines (JAL) fly there.  The only bad thing is that JAL has only 1 daily flight and it is an early one.  All of AA and JAL flights arrive into Tokyo too late to make the connect and thus require an overnight in Tokyo.   I am planning on using Cathay Pacific as they has pretty good award availability from their North American gateways and they have 2 daily flights to Guangzhou.  They include:

• (LAX) Los Angeles- 3 Daily flights 
• (SFO) San Francisco- 2 Daily Flights 
• (ORD) Chicago- 1 Daily Flight 
• (JFK) New York JFK- 3 Daily Non-Stop Flights and 1 via Vancouver 
• (YYZ) Toronto- 2 Daily Flights 
• (YVR) Vancouver- 2 Daily Flights

Here's my outbound:

The problem is that transiting through Toronto requires me to clear Canadian Immigration/Customs on both the inbound and outbound flights.  Cathay Pacific uses the ghetto KLM lounge there and I am not looking forward to transit Toronto on this trip.  I have limited choices as I want to maximize my time in the China and leave during the night to a Cathay Gateway and take the midnight departure to HKG.  That leaves me with LAX (2 flights), SFO, YVR, and YYZ to take advantage of that.  I am looking for LAX or SFO to avoid Canada.  LAX has both the AA Flagship Lounge and OneWorld Lounge for me to use while SFO has a nice AA Admiral's Club and CX Lounge so they make an excellent choice.  LAX has the new Cirrus Business Class while SFO has the old Business Class Herringbone Seats but on a Boeing 747.  I hope to get on one of these routes and a First Class award seat opens up.