I've only owned two enlargers, an Omega B600 and a B22. I aligned both of them w/ small levels, making sure the lens board was the same as the base. Always got sharp prints. I was thinking that since I usually stop down to f5.6 or more, that would probably cover any errors? All I know is DOF w/ a camera lens, and if I were shooting a 50mm or 75mm on a 35mm camera, the same focal length of my 2 enlarging lenses, f8 would cover a multitude of sins. Even considering that an enlarger is blowing up a small negative many, many times, wouldn't the same sort of DOF apply? Not a direct correlation of course, but when in doubt stop it down as long as you don't have real long exposures?