Top, before. Middle, right after. Bottom, after excess has been scraped and pushed back flush with studs, about 24 hours later.
As it cures it sounds like you're in a bubblebath.
The screen bowed out quite a bit with the weight of the airkrete. We had planned for that by furring out the ceiling. But the walls, also, bowed out. We waited about 24 hours until the insulation had enough strength to stay put when pushed back, then used a concrete finishing tool to scrape off excess and gently push it back. We lost a little of the insulation properties in the innermost inch or so because we squished the bubbles. But it wasn't much, and better than having to put furring strips on all the joists on all the walls in order to have smooth gypsum wallboard.