The telescope is out of the bracket at the moment. I made a small rest some time ago as you explained in one of your articles for centering the telescope ( I did these for my MkI telescope). In these rest I can level the crosswire to my wallchart that I use for classroom boresighting.
As I look trough the telescope I have the impression that the crosswire and post are square. When I level the crosswire horizontaly it does not appear to be parallel with the range or square to the deflection drum.