Just flew ATL-LAX, 4:30pm flight today. There were 17 seats open today, then at the gate, 13 seats. I was #15 of 26 as GM on a U fare

. Should have just done that MR for PM last year ...
Then again, it was the 767-300 so the ratio of F:Y is poor. I chose that because I rarely get UG'd as a GM on that route, and had 10A which is one of my preferred seats on that plane and better than 3-3 seating on a 757.
Some would say that the midnight redeye on Sunday (arriving Monday morning) is tough, but I once got it as an FO ... it really depends on the flight. I'd say that 757s during non-business hours are your best bet, as the F:Y ratio is better + less elites to contend with.