Thank you, recent posters.
I've been lax in providing updates for the half a dozen or so challenges I haven't covered because:
(a) Overall they are harder, and by nature, I've been shooting for the hardest ones first.
(b) I don't like trying to sound like an authority without having actually done the leg-work.
For example, I was QUITE prepared to tell you how miserable flat-calling with pocket sixes or better with a mid-size stack was going to be in 27-person tournaments. But after actually doing the challenge more than the first few times, I'm ready to downgrade it from "nightmarish" to merely "awful."
You can still go dozens of games without the opportunity popping up, but it does seem to happen organically more than I first thought it did.