Aspidustra
You're only showing yourself as being well-informed about the astronomy for real! We know about JAA ATPL navigation, Oxford Blue may know a little more. Sorry if I was a bit short wiht you, not intended. Our students don't usually like this section of the course, although it is not as difficult as some persuade themselves it is.
Hour angle of -120°/-8 hours would be the same as +240°/+16 hours, although we only ever look at positive hour angles, measured West of the Greenwich Hour Circle.