Here it is.
Upper photo: on 17-31mm extension, which allows for infinity focus on the Z system. There will be some corner vignetting on the FX bodies thus I more often use the 55 CRT on DX format.
The slimmest solution will be an M42-M42 focusing helicoid, add a flat M42-Z adapter at the rear and insert the 39mm-42mm ring in front.
Below is the 55 CRT with my bespoke F adapter, complete with CPU. Can be used on F systems or on the Z via FTZ/FTZ.2 with EXIF information available, but only for close-ups.