[dredmorbius]

I've settled on the following word list to determine if 20 of 26 characters are present within 4 guesses:

  thank
  fuels
  crowd
  gimpy

If there are fewer than 5 letters present, "bevvy" will eliminate another two ('b' and 'v'), leaving j, q, x, and z as the remaining possible characters. These occur rarely (though "pizza", "bijou", and "vixen" can be challenging targets. More usually, it's words with either doubled characters, such as "onion" or "lalai", or those which have viable anagrams ("spams" and "spasm", "donor" and "rondo") that will throw me.

[ghaff]

The thing is that this doesn't help you with double letters, still leaves out some less common letters, and leaves you with very little margin for error at that point.

On Octordle, 4 words seem easiest although it makes the game more of an anagram solving exercise and in my limited experience didn't give me much of a consistent score advantage vs. three.

[dredmorbius]

I've used that strategy on 100s of standard Wordle games to good effect. It's not perfect, but it solves ~98-99% of all games attempted.

(That stat comes from one of the multi-play Wordle imitations which does in fact track success rates.)

I don't recall mean attempts, though I believe it's still between 3-4 tries.

Once most characters are tested, it's usually pretty clear what the actual word is, and some familiarity with the actual wordlist (which I picked up merely by playing the game, not by examining source), the harder cases also become pretty obvious.

Doubled letters and anagrams are the most difficult cases.