If you want 'the definitive' KJV, I would suggest you need the New Cambridge Paragraph edition. The one I saw was about £20, but there were a variety of prices depending on the binding.
I've read the introductory essay (a while ago). It has gone back to the original Hebrew and Greek documents used by the original translators, and looked at the first edition published in James's reign.
I think it argues that the printers introduced some 'corrections' just after James's reign, and that all subsequent editions have been based on the 'corrected' edition. From what I recall, there was some discussion about subtle differences (for example "MY SELF" has a slightly different meaning to "MYSELF").
I'm not sure that all of the above is THAT relevant to the average reader. But it did make a good case for being 'definitive'.
What's more important about the New Cambridge Paragraph edition is that it is not laid out in two densely-packed columns per page, as most Bibles are, but all the prose works (histories, narratives) are laid out in paragraphs, making it more 'normal' to read.
And all the songs, Psalms, and prophecies are laid out on the page like poetry.
It makes you more aware that certain parts are more metaphorical, more lyrical, more beautiful. And perhaps not necessarily to be taken literally?