At least 3 days if on a busy night or weekend. I've been able to walk in for most lunch's and week night dinners
We were a party of 12 and we called a month out and they couldn't take us until 9:30 pm on a Saturday night. We were able to get 6:40 pm on Friday night.
For busy seatings I definitely recommend 3 days. For off hour seating you should be able to call ahead and on most off-peak times you can usually walk-in with a minimal wait.
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