great question....hope you won't mind if I add on to this.
How early do you suggest we arrive at port to get a number 2 boarding pass?
And when boarding time comes, the difference between and 2 and a 5 (for example) is only a matter of minutes!
We had #13 and got on about 20 minutes after boardiing started.
I arrived around 10:30, with my two girls in tow, and got #5. My DH came a few minutes afterwards, and got #3.
BTW - everyone gets a card and then categories 1-3 get a number one card at check in
Barb