If you want to get your restaurants it seems obvious to have the biggest but I also say smallest could work as well. Pizza Barn has done the extra large with a 2 foot slice which a wall of celebrities have taken a bite along with a line of people wanting to as well… if they can. Yet having the smallest can work as well especially if it has a unique high quality to it, think of expresso as an example. Many want to taste something that is extraordinarily good and or unique even if it is less then a bite. In a world where competition is knocking at your door make sure your door is extra large or small and people will continue to open yours instead.