Since the discussion is about how reference books are to deal with this discrepancy and I cited an existing example. Clearly, they're going to keep insisting the original Enterprise is 289m.Which are - you guessed it - non-canon. Eaglemoss can tell me the Runabout exists in a 200m battle-version. That won't make it true either.
The "common" given size for the Connie is simply a mistake (again - taken from an earlier draft where the ship had half the deck-count), that simply was never corrected, because no one cared enough, and it wasn't official anyway.
And again, even if they were the same length, the proportions won't sync up enough for either to be a plausible refit/defit.