There’s no specs on the ship anywhere. I had to guess at it’s size by finding an in between based on the ship in front of the Enterprise and behind it and comparing that to known features on the E like the bridge. I guessed, considering the Tholians are unlike any life ever seen that their materials (which have to contain massive amounts of heat and still function) where also like nothing we’ve ever seen. The ship is small, but it’s 100,000 tons heavier than the Enterprise. It has no decks as we understand them. Despite its size the crew is 200 strong because who knows how big a Tholian is (ignoring ENT). Certainly if they were human proportioned no realistic amount of them would fit in a ship this size with a plasma cannon and a web spinner plus all the other engineering requirements.
There is no doubt that Jefferies was a master draftsman. The Tholian ship was done on the cheap, with a relatively simple design – no protruding engines, windows, or differentiated hulls. Just three fins. Still, Jefferies made sure the shape was complex and unique. The fins of the ship thicken and taper creating all kinds of contrasting angles. Tilt the ship in any direction and you get a new, unexpected silhouette. Looking at it in this kind of detail makes me even more miffed that it was replaced with the much more generic looking design in the Remastered edition of TOS.