Pretty awful route, to be honest. I stayed away from it all the time when I was a GM (had much better luck on CVG-LAX/MSP-LAX) and even as a PM or DM, this is difficult.

If you want to maximize your chances on ATL-LAX, I would avoid flights on the 763. I believe it has the worst F/Y ratio of the craft that fly this route. In addition, the seat pitch in F isn't so wonderful anyway. If I was going to pay for F on ATL-LAX, it's definitely not on the 763 unless that's the only flight that will work with my schedule.

Also, one time I boarded a 763 and it reeked of fish. This led to a 4-hour mechanical delay.