In Harmony D’Andrea’s eight years as a server at the Big Texan Steak Ranch, in Amarillo, she’s watched hundreds of competitors take their shots at the 72-ounce steak challenge: eating a shrimp cocktail, a baked potato, a salad, a buttered roll, and a 72-ounce steak in one hour. D’Andrea has served all kinds, from confident carnivores to those who realize—too late—that they may have bitten off more than they can chew. Her advice? Order the steak rare, and bring a sharp knife. “Sometimes our knives have had it,” she admits. As to whether she’d ever take on the challenge herself? “I’m not a sirloin girl. I’m a ribeye girl—that’s my excuse,” she says with a laugh. “We do have a lot of employees that do, though. But…