This has come up in another forum that the original concept for the NCC-1701 called for a 540 foot-long ship design which Matt Jeffries changed to 1,080 feet. While Matt Jeffries had later stated the ship to be 947 feet in length, it would appear that at least one ST-fan had actually measured the ship based on various markings on the ships hull and confirmed the 1,080 foot figure.
The facts are that Jefferies didn't change the length (at any point) to 1080 feet, and the hull markings you are referring to only supported the original 540 foot length which existed before the final plans were finished (and models constructed) and never implied anything else. In fact those markings only made sense (as I recall) if you included the original dome cover over the dish on the secondary hull (which was absent from the final construction plans).
If you want a longer ship, use
a longer ship. But please don't misstate the facts as some form of justification for it. If you don't care for the show's facts, ignore them (this is all fiction after all). But clouding the historical facts of the original production is messing with real