It would be better, unless you're ready to spend a good amount of time drinking on the drink deck. Which is awesome. But I'd call in advance anyway for such a large party.
It depends on what time you're going to be there. Not too many people in the afternoon on regular days. Weekends are busy, so call just to make sure they could accommodate you. Also, it's not the just seating, but having enough wait staff to serve your large group.
Show up and write your name on clip board immediately upon arriving then order drink at bar.
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