We did Twilight check in last year and it worked out very well, we live quite close so went up the previous day. Although had pre booked seats still changed to nicer ones at check in, still upstairs in PE. Had to wait for half an hour after check in as advised may need us to open cases for further checks, this was ok as had to get our FX that was pre ordered.
Following day was great arrived walked in no luggage and straight through to departures
Claire