Hi KH, and welcome.
I'm afraid that isn't a super straight-forward question to answer, though that's not to say some peoplee on this forum won't have equivalent experiences to share. Sizing differs at every store, and I'm not sure what ATL's measurements are like relative to other brands. With jeans, though, it's more of a direct measurement. If you know your waist or hip measurement in inches, that will be most effective for determining the size of premium denim you need. Like I said, though, I defer to Angie and others for true expert input.