So that would result in hours of varying duration (from, say, winter to summer)? And minutes would get longer at night, in the winter, except at the equator? And would it be a minute or a second or ?? that defines the period from sunrise to sunset north of the Arctic Cirle in the summer?

And how should I calculate my location -- whether with a sextant and slide-rule or with a GPS? Either is going to have a hard time with definitions of units of time "relative to sunrise/sunset."