The Einstellmattscheibe is supplied in a plastic box incl. Special tweezers. The exchange of Einstellmattscheibe is quite simple with a steady hand, fortunately, thanks to the included tweezers: A flap on the camera is open, it takes the old ground glass, positions the new, still not quite close the door and you're done ... no: Because adjusting the exposure of the camera nor the individual function (C.Fn-00) has the new adjustment shims are communicated.
For Nikon (eg D70, D200, D300) can be seen that it is possible Display Grid Linen additionally without changing the focusing screen. This solution would have helped also by Canon and therefore 2 points deduction.