I intend on building my own 4x5 camera very soon. The body will mostly be made of hardwood. The research I've done states that the ground glass has to be directly on the film plane to achieve proper focusing. The issue is, I'm not sure of exactly how precise I have to be while building the camera. I'm wondering if anyone can perhaps provide building tips and/or suggestions in order for me to tackle this issue while designing and building my camera. Many Thanks, Derek.