For me, it depends on what the overtime consists of. If I'm starting before my start time to do EAMS of preload or doing a PM air route after my shift, then I could work 11.5 for the rest of my career. If I have to parcel in the pitch black and freezing cold to get 11.5, then I want no part of it. 9 hours/day is perfect for me.
Is it funny, most of blue collar world exists on 40 hours/week. 6-230, 7-330. Can you image getting out at 2:30 and have worked a full day? It would be like a part-time job for us! I don't know about you, but I'm still burping my lunch out at 2:30 and I'm awake by 5 am every day. Sorry for the disgusting image...