Could MS (Std & Pro) just have a 'Turntable' setting in the align dialog? Or even a bit auto-detection?
Turntable scans are 'always' vertical (unless you're scanning on a lathe! lol)... which means the axis of every scan level should be vertical too, and should also be coincident (unless handheld)... Which gives you the axis of the turntable itself.
Surely ms can calculate this axis of any level of aligned cameras, and then, as the 'Turntable' setting is checked, it would correctly orientate the scan vertically, and the right way up... ...using the assumption that most scans will be 'looking down' on the object... but perhaps with an 'inverted' checkbox or tool, if the scan is say of a monument, scanned by hand, whereby all levels may be lower than the object.
MS should be able to correctly orientate almost every single turntable scan. With the axis on the z axis.
There should be no need for any markers or any extra work to have these correctly orientated.
But again, IF we could have a subset of the reference system, with a few markers available in the Standard version, it would be so, so useful!!!