That's what I'm saying use the laser, Mark the spot before cranking the head then realine to that spot and lock up the head. It should be close. It would be straight up + down in the same plane. Parallel.
Yes I definitely get that. Was just thinking if a guy had a nice flat and straight bar set up parallel with the column and an indicator mounted to the head as long as you do not swing the head it would be easier to get back to zero. Although if you swung the head to one side it could be limiting the swing. The laser would certainly eliminate that issue. The creativity here certainly makes this a good place to be combined with the fact no one flames you for adding your thoughts!