Note that it is important to align the negative and the sensor. Absolute alignment in relation to gravity doesn’t matter.
BTW: Nisi rails have those threads for feet. All you need now is some perforated plate(s) that can attach to the rail and to the column with fitting screws and a couple of slot nuts…or one or preferably two arca style clamps holding the rail. For adjustment, you could add tape to compensate tilt or use blades of a feeler gauge set…if the column is sturdy enough to make it worthwhile.