"Yesterday I received a Parallel laser leveling device. It was very easy to get the lens in perfect alignment with the baseboard of the enlarger. I also checked the negative stage and it's a bit off, but I don't see any means for adjustment. Is there something I'm missing?"
FIRST, check that the mounting screws for the frame to base board are tightened. Where the head assm. mounts to the chassis to pivot are 2 screws from the rear, loosen these to adjust for left-right alignment, recheck while tightening. Use the adjuster bolt at the bottom the adjust front-back alignment. Recheck lens alignment with the lens adjustment screw for left-right alignment, front-back alignment should be spot-on to the neg. stage unless the unit was dropped.