The float test is usually used only at the end of hatching to check if an egg is alive. Small movents are easier to see in a floating egg than they are in an egg sitting in the incubator. But it's usually a bad idea because if there's cracking or an external pip that isn't obvious you can drown the gosling.
Misting is recommended during incubation to help soften the shell leading up to hatching. But it's possible for the eggs to hatch without it. Some people who incubate eggs don't mist and cool the eggs at all. You want to do it once a day, preferably while the hen is off the eggs. Use water approximately the same temp as the air and, depending on the size of your nozzle, a sqirt or two per egg. You aren't trying to soak them, just get them damp.
