This gauge will check the cartographer height 2.6-3.0mm It also has a mark to show where the nozzle should be for the offset.

I have uploaded stl files that are common and defined in Simple AF

The varset shows offsets as absolute numbers, no negative signs.

It is setup for a nozzle Z height above the bed at 10mm for checking. I home it to a Z of 10mm and tweak it to just touch the top of the gauge by turning the z lead screws with my fingers.

The FreeCAD file has 3 var set values you can change and export the model with the new settings.

Height_High 3.00 mm
Height_Low 2.60 mm 
Offset_Mark As needed

I setup and check initially with a digital caliper. This tool is good to do a quick check if you think the mount has moved or warped. You can us it to check the front, rear and sides of the pcb to be sure it is mostly parallel with the bed.