I always take the 6am flight out of JFK when headed to Asia via SFO, regardless of when the SFO-Asia flight leaves. There is nothing worse than sweating out whether or not you make the connection for the 6 hours it takes to get to SFO, and I can hang out at the RCC and do work emails which is good because it means I'm not separated from work for a 24 hour stretch. Of course, leaving JFK as early as poosible in the day is never a bad idea either :-)