In other words, they're about as authoritative as TOS itself. 
A lot of this boils down to bouncing back and forth between putting together what's depicted on screen and putting together what works and looking up on screen references to justify it.
Fortunately, so many of the tech references are so all over the map that it's not hard to do, just as it's possible to justify Cary's version, or Aridas', of FJ's, for that matter. It's all a question of which parts to embrace and which to ignore.

A lot of this boils down to bouncing back and forth between putting together what's depicted on screen and putting together what works and looking up on screen references to justify it.
Fortunately, so many of the tech references are so all over the map that it's not hard to do, just as it's possible to justify Cary's version, or Aridas', of FJ's, for that matter. It's all a question of which parts to embrace and which to ignore.