First of all your post stated an 1130 pm departure. That impresses upon me your need for sleep. If you like to recline immediately upon entry on all flights, then so be it. I do understand the point of this thread is to understand the "official" CO policy regarding reclining before takeoff. I have had the occasion to board late in BF on 762 and 764. I do admit I seldom fly continental other than from LAX to HNL to GUM, so I am not familiar with the 752's. Nevertheless to address your initial inquiry, I have asked people in front of me, most of which are CO employees in BF (another thread), to move their seatbacks up to allow me better access to the area under the seat in front of me and never had a problem. I also have never had to escalate this to the FA so I can't tell you whether they would have supported me on this. It can be tight behind the seats in this BF arrangement, once the seat in front of you is reclined. I realize I do not have 4000+ posts to my name and do not have your experience on FT, nonetheless I do have a great experience with the airline and hope that if it is not a policy to enforce keeping seatbacks up before takeoff, it should be.
That said, if the plane is in a delayed situation, and takeoff is nowhere in sight, I do agree that rules should be relaxed. All of this is common sense.
I do agree with the original post that if the OP is seated, slightly reclined, (not on someone's lap) on a red-eye, and the people behind are seated comfortably, and reading, listening to music, etc. There is no reason to enforce some policy, regardless of the rule, if everyone is happy.