Since online booking has an hour head start, I'd just do it online. You have to book one room at a time but at least you'll have access before MS opens.
on-line you can do it 1 room at a time , just be sure to do the hardest room category first. Also don't try to add all guests at that time, just use 1 name and move on to the next room.
on-line you can do it 1 room at a time , just be sure to do the hardest room category first. Also don't try to add all guests at that time, just use 1 name and move on to the next room.