Planning to attend and participate in my first CTP, looking forward to it.

As it'll be pretty damn early (3:00am local) I'm trying to minimize workload on clearances and had a few questions based on the Aviation Pro video I watched on YouTube the other day.

1.) Will I be requesting oceanic clearance on the ground or shortly after takeoff? The video mentions 3* as the cutoff and I understand EGPH to be right around that.

2.) Is there a preferred route. I understand that the NAT tracks have not yet been published for the time zones that this event is taking place. I'm using this website as a reference point - https://pilotweb.nas.faa.gov/common/nat.html

3.) What is standard/customary for stepping away from the 'pit? I'm a short haul flyer, nothing over 3 hours so I want to be respectful to all controllers but I also know I'll need some breaks once in a while.

Lastly, if there's a good web-based resource beyond the AviationPro video from a year ago to reference, please feel free to just direct me there. Happy to do my homework.