If I cut in in half in individual soufflé dishes, how long do I bake it from if prepared the day before and brought to cool room temp?

The Washington Post recipe I mentioned in the article recommends 20-25 minutes (and probably a little longer, depending how cool they are to start) but it will depend a bit on the size and material of the dishes, too. I'd recommend hanging out with a glass of wine in the kitchen and sitting down to eat when you see them rise and get nice and golden—it shouldn't be more than a 10 or 15 minute window of uncertainty.