...of the supplemental texts. Tolkien changed his mind about many things,
or recorded many speculations, and though they are printed in the HoME books
and others, they support for certain only the fact that at some time, Tolkien
had this thought. Whether or not it applies to the finalized version of
the work as a whole... that's something else, and difficult to say. For
myself, as a writer, I would put more credence into what he said in his letters
than in the HoME passage; the letter appears in a much more developed
discourse, whereas the passage in TToI seems much like many of my own notes
that I make during my work on a book in progress. They are not absolute;
they can and do often change before I write the final version of the
book. The passage in Letters also seems to me to be more in line with
what we actually see in LotR; that from TToI does not quite seem to fit, since
there is no supportive evidence in LotR itself that says for certain
that Frodo ever used the Ring, above and beyond putting it on to become
invisible (at least not that I can recall).
I believe an argument can be made for either side -- did he USE the Ring's
power or not? -- but it's a matter of personal opinion as to which feels right
to the individual
reader.