A design process for varying hole locations or sizes or both in an ion beam grid includes identifying a control grid to be modified; obtaining a change factor for the grid pattern; and using the change factor to generate a new grid pattern. The change factor is one or both of a hole location change factor or a hole diameter change factor. Also included is an ion beam grid having the characteristic of hole locations or sizes or both defined by a change factor modification of control grid hole locations or sizes or both.