Chris, please tell us more about what you're doing. You shouldn't be having such horrible problems.

FWIW, I shoot closeup -- up to around 2:1 -- on 2x3. I normally set magnification first by setting film-plane to lens diaphragm distance with a tape measure. The distance = f*(1 + m). f is the lens' focal length, m is desired magnification. And then diaphragm to subject distance is approximately f*(1 + m)/m. Understand that these distances are very approximate, the lens' nodes probably aren't at the diaphragm and its hard to locate the film plane precisely with a tape measure. But they're good enough for initial set up.

And then I fine tune focus with a focusing rail and, sometimes, moving the front standard a tiny tiny bit. Focusing rail is better.

If the subject isn't immobilized, things get very dodgy. That's why I still shoot closeup with a Nikon and KM (deepfreeze isn't empty yet) and flash illumination.