Flying to Los Angeles in a few weeks, where should I go for upgrades

I am flying RDU to Los Angeles. I will be leaving Friday morning and returning Monday night (possibly redeye?). I am wondering what flights I should take for upgrades. I am a DM member and will most likely book a few days in advance. I am just looking for upgrades with the best flight. Of course I love the lie flat idea, for sleep, I could take the direct from RDU-LAX. However, my closest airport in LA is SNA. Should I do Ontario, SNA or LAX?

I can also do Thursday afternoon vs Friday morning. Very flexible (compared to most of my bookings.