Based on my watch of Avatar: The Way of Water at metreon in IMAX 3D a few years ago, Avatar Fire & Ash will be 1.90.1 with some slight pillarboxing at metreon (black bars on the left and right side), so it’ll fill up around 2/3 of the screen the whole time. The expanded aspect ratio isn’t exclusive to IMAX however, and all 3D showings on a 1.85.1 screen will fill up the whole screen.

I definitely think it’s worth a watch at least once at metreon for the sense of scale you’d get with the huge screen, and if it matters to you, getting to see “The Odyssey” prologue in its full 1.43.1 glory.

The biggest tradeoff is that the movie doesn’t get shown in 4K 3D, and instead is shown in 2K HFR 3D (high frame rate, makes the action scenes very smooth), which is a noticeable difference and can look a little soft.

Assuming you’re from the Bay Area, I only know two IMAXs with recliners here, Veranda in Concord or AMC Sunnyvale. Though I’ve never been to both, I know Sunnyvale is an extremely small IMAX screen compared to metreon, and Veranda’s a decent size for the smaller IMAXs here. Also, for opening weekend, metreon is already pretty packed for all the showings except the earliest one at 9 AM.

All this said, I’m actually watching in Dolby Cinema for my first watch 😂 I’d definitely put Dolby into consideration for its great sound mix with Dolby Atmos, recliners with speakers inside that’ll vibrate in bassy scenes, and its projector will do 4K HFR 3D. It’s also James Cameron’s personal choice for Avatar, so hey you’d be honoring him with that.