My mind always searches for concise general rules from which all details will flow.
Have read a multitude of articles about how to mount to avoid parallax and all have dealt with the whys and the how to's. I've concluded two general rules which I think will apply with both of my heads - the NN5 and the M1-L, and maybe others as well.
1. The position at which the lower rail clamps to the tripod mount is dependent solely upon the camera body and the manor and parts attaching it to the upper rail (nadir adaptor or not, camera plate, clamp attaching the body to the rail, where the vertical rail is attached to the lower rail, etc.). Any lens may be used to acquire this positioning.
2. The position at which the camera is stopped on the upper rail is governed solely by the lens and the focal lenght to be used for this panorama.