Beautiful explanation that feels credible and real.
I hope I got that right. You calculated an average deck height of 12' for the Grissom?
That would seem like too much overhead space for a vessel as small as this to me.
I think it all comes down whether you feel that the latest "contradiction" overwrites previous continuity and takes its place or whether the previous continuity remains intact and the "contradiction" requires rationalization.
The depiction of the Enterprise-
B doesn't cause me headaches. I rather think that was some kind of upgrade to improve transwarp performance and/or reduce the adverse physical effects it might have had on the crew. Eventually they reduced the volume of these components and became able to retrofit the ship to its original appearance (as displayed in the conference lounge), which is actually how I remember seeing most Excelsior's
in TNG (although several of these - from a production point of view - were apparently stand-ins for Probert's unvisualized Ambassador Class, e.g. USS Fearless