On an upcoming trip, I'll be flying from Dublin to the USA, on a flight which has US pre-clearance in Dublin.
I'm reasonably happy (based on experiences) about how far in advance I need to get to Dublin airport for a normal international departure, to cover checkin + security + walking + etc. However, I've not taken a pre-clearance flight before.
When factoring in when to get to Dublin airport, for a pre-clearance flight where I'll need to go through US customs and immigration in Dublin, how much extra time do I need to allow for the US pre-clearance formalities?