lord of the rings - Why does Cirdan give Narya to Gandalf instead of Saruman?

Cirdan gives Gandalf his ring because

"from their first meeting at the Grey Havens [Cirdan] divined in [Gandalf] the greatest spirit and the wisest; and he welcomed him with reverence, and he gave to his keeping the Third Ring, Narya the Red.", Unfinished Tales, The Istari (called by C. Tolkien, "essay on the Istari").

In his editorial comments immediately following the essay, C. Tolkien notes "Cirdan's perception that Gandalf was the greatest of [the Istari]".

However, in a late note (possibly from 1972, cited soon after in the same chapter), Tolkien writes that Gandalf was "evidently the next in order" below Saruman in "Valinorean stature". Like other puzzles in LotR, when the foregoing is taken together with statements elsewhere that Saruman was the greatest of the Istari (e.g., Two Towers III 8 - "chief of Wizards", Fellowship II 2 - at Council, Gandalf: "Saruman ... is the greatest of my order") the answer tends be to unclear. Even so, Cirdan sees something in Gandalf greater, wiser, and more worthy than Saruman. In hindsight, Cirdan was right in perceiving that Gandalf would remain true to his purpose, while Saruman would not.