I'm staying the night before at the Four Points across T3 so traffic won't be an issue. The only thing is that the hotel has the shuttle only at the top or the bottom of the hour. So I can board the shuttle either at 4:30 or at 5:00. I would prefer the 5:00 am but that would drop me of the T1 probably around 5:20 a.m. the latest. The 4:30 am shuttle would get me probably being too early at the gate (before 5:30 by my reckoning).