When I started using AutoCad for Mac years ago in 2011 I believe I found a way to use multiple units in the same drawing.

Everything was drawn in millimeters but when annotating it showed both in mm and shaky at once.

FYI: Shaku is a Japanese measurement unit and equals approximately 303mm/1 shaku

I remember it wasn't all that complicated to set it up and worked perfectly for years. In the mean time I have migrated to a new system and newer versions of AutoCAD but can't find out how to set it up as I used to.

So my question is multifold:

How do you set up a project to show two measurements at the same time when annotating?

And how to do you setup a custom measurement unit? 

All help is welcome!