Quote Originally Posted by Bill Burk View Post
Sounds to me like you should focus by eye... Make print and develop to confirm it's still best... then without changing the focus, put the grain focusers down to see which ones confirm the focus... If the direction of error is "up" you could put something significantly thick under the focuser to correct the error. (But if the direction is "down", you're stuck there).
If they really are off they will need to be lifted or sunken a few millimeters if not centimeters to see any difference.

I'd suggest just adjusting the eyepiece on all of them. I suspect the issue in the OP is in correctly viewing the aerial image.