Karnak is right, you need to look at your planeset and figure out what stations are most common and go down from there. The lanc pretty much dictates the 2-3-4 being Nose-Upper-Tail, then the 26s/25s give you 5-6 as Left-Right, finally the Ball forms #7. That being said I also agree with APDrone. While the layout Lusche put out is a good default, I absolutely would love to have a customizable gunner position key call.