Some diners at Hurricane Grill & Wings had been limiting themselves to a small order of the chain’s saucy chicken wings and a glass of tap water. These days, many of those people are upgrading to a bigger order of as many as 15 wings and a soda. For Hurricane Grill, which sells its wings in more than 30 varieties of sauces, the larger plates and the sodas are a sign that customers are OK about spending a little more when they go out to eat. The evidence may not be a big economic report like gross domestic product or factory orders in a region, but small businesses have their own indicators that the economy is improving.