According to the Datin dimensions the shuttlebay model would have a length of 122' or 37.2 meters in real life.
The Jefferies cross-section would suggest that the observation corridor began somewhere around 356' and ends at the stern at 478'. That's exactly 122'!
Although Matt Jefferies had suggested a shorter length in his The Making of Star Trek
TOS cross-section his Phase II cross-section now obviously tells us that he accepted and approved the bigger VFX model and authenticated its dimensions by reflecting these in his "new" cross-section.
Regarding the circular "hatch" I'm somewhat unable to link this one to the Mike Minor intermix shaft. We have other vertical structures in the cross section but none corresponding with the yellow circle, which has moved considerably further stern compared to the TOS Enterprise
It almost appears there's extra storage in the vicinity above the observation corridor for small shuttles or Probert Workbees but not an engineering room.
And the length of the engineering hull has almost jumped from 340' (TOS Enterprise at 947' O.L. without main sensor) to 478'. Is there something I missed?