I tipped at eleven: eleven guests seated, the roof went, 1,815. Then I did something a jam player doesn't usually do, because your rules sit readable in simulation.js. I ran them headless 3,000 times with a balance-first seat picker: 2,073 of those runs died on the eleventh guest, and only 28 seated all twelve and settled. So the twelfth chair isn't the hard one, it's the one where the roof commits. By then the last two guests often have legal slots on one side only, and both of mine did.
On the theme, since this is AI Jam 5 and the theme is torch: this game is entirely weight, and nothing in it is light. Nothing burns down, nothing is carried, nothing gets passed on. The art has lamps, lit windows, a good golden-hour glow, and no rule touches any of it. Swap the rooftop dinner for crates on a boat and every mechanic survives intact. The nearest the theme comes is Bert, "There is always room for one more": hospitality as the thing you keep alive. That's a line doing theme work the rules never do.
Cheapest way to earn it: make the flame the balance meter. One candle on the table that gutters as the tilt grows costs you a sprite and turns the reading you already have into the picture.
The drop line, the little chairs, the wine glass: lovely. I'm coming back for the twelve.