Do you mean in your own cabin (which class?), or are you planning to cross cabins or deputize an FA to distribute to others?
Not really answering your question, but I would suggest giving to those FAs you directly interact with, as you do so, rather than hunting down every single one. When they take an order or serve you something, they get a card if they haven't already. Six should be enough for those serving your specific aisle over the flight.