A more important reason for the turbolift bulge being on the lengthwise axis is that the filming model had to be symmetrical. It was only ever filmed from the right (starboard) side. If it was non-symmetrical, the turbolift bulge would have alternated between sides depending on which side you seemed to be looking at.
Adam Savage has a video where he visited the original filming model at the Smithsonian and he and a conservator go into detail on that. Whenever you see an original shot where it looks like you're seeing the port side, they actually filmed the starboard side using mirrored decals, and flipped the film horizontally in postproduction.