Hi author, I really liked the visualisations, especially the black hole thing.
I think I may have misunderstood the purpose of your article: I first read it as a serious attempt to use textual analysis to do a comparison of the comprehensibility of Tolkein's best-known works, in which case you fell way short of the mark by going no further than word counting. I think it started off like that, but on re-reading it I see that you say you hit a brick wall (paraphrasing) and decided to have some fun visualising your results so far; something you did very nicely. So perhaps I got the wrong end of the stick.
I thought about what you've taken on here. Doing things at the word level is pretty easy. Taking into account grammatical structure to get things like sentence lengths and clauses per sentence, or breaking words up into syllables (needed for F-K, for example) is considerably harder. I'm interested to hear what you come up with. Flesch & Flesch-Kincaid are US inventions so perhaps not obvious to everyone.
On he/she: I agonised over that for a good ten minutes over my breakfast. I read around your blog and your twitter page this morning for clues as to the appropriate pronoun. In the end I couldn't tell, so I went with 'he' because I stereotyped you. I nearly changed my wording to use constructions like "the author," "they," and various other mealy-mouthed alternatives but they were too ugly. So I did try, but I got it wrong. I apologise.