Could you please suggest some ways and tips on how to make sure a new ground glass is correctly registered? It's not that much of a problem when the ground glass is exchanged for another plain ground glass, but it becomes difficult when one wants to replace for instance an original Fresnel-gg combo where the fresnel in on the lens side, by another system such as a Bosscreen (or Beatie, Maxwell...). What I have done so far was set the camera with a luminous lens on and focus on something, then replace the set and check if my focus was still accurate. But I'm not sure if this is precise enough. Any better way that you could suggest? Also on my specific set (Toyo VX-125), the Fresnel-gg combo places the focus plan a little further towards the lens than the metal bed where the gg sits (Fresnel on lens side). The other way would have been cared for easily by placing some wedges in between, but now I feel that I am stuck. Right?