On exploring the various threads here, I've found an extraordinarily wide-ranging height for strings.... I know comfort plays a large role, but is there any sort of industry standard?

Nope, no standard. Action affects tone and playability and its all personal preference.

and those measurements are taken from the octave?

Thats another subjective point. Some basses have a FB that curves up slightly, others are flat, so a measurement at the end of the fb or middle may not be representative of the overall feel

Canuk, from where on the neck are you measuring?

Thanks guys