A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2019 Jun 11, 09:18 -0700
In case you can't find the book - here is a scan of it.
The actual method is on the pages 53 and on.
I do not like to complement angles, just take all the minutes values as read off the drum and prepend them with proper degrees (with 359° if the index is to the right of 0° - "off-scale"; with 360° if the index is to the left - "on-scale"). This is straightforward and robust against any computation errors. What you get is what you use - algebraically - in the HS correction process. No need to change signs, etc.