Assuming you don't have an extender chip, your normal idle AF readings should be 5 or 6 while in park.
WOT readings will vary widely depending on the car's setup/equipment, and boost levels.
A stock GN pushing 12-13# of stock boost might get as high as the 230 range or so. Once you start approaching 15# or higher it should be able to get close to or hit 255 (the max available). Over 15# of boost and it will top out at 255 much sooner, etc.