Same here, start by getting everything (baseboard/column/lens stage/neg stage/head) levelled using a spirit level, then use a scratched piece of film and carry out the fine adjustments.
Bear in mind that the lens and negative stages use two grub screws to lock the swing detent......so be sure to loosen both screws before you adjust, then lock down the opposing screw. I think Greg shows how it's done in his video.
Mike
