Bid the things that will screw you last. There's no 220 in ATL so if you wanna be ATL based, 220 is your last preference. First preference is every ATL offering, second tier is every plane that ATL has but NYC based so you can base swap on the next AE (usually couple months). Last tier is stuff that doesn't exist in your desired base. You can bid for a new category after only a 1-year seat lock in that case (remaining seat lock gets added to your new seat lock).