I think you can do a combination of room-temperature and cold fermentation over the 21-hour period. I also think you can use either order, that is, start with a room-temperature fermentation and finish with a cold fermentation, or vice versa. The choice will most likely be governed by your personal schedule. For example, you could put the dough in the refrigerator tonight and bring it to room temperature in the morning, before heading to work, etc. If you use the reverse sequence, you will have to allow time for the dough to warm up before using.
I think you might also be able to go a full 21-hour cold fermentation or a full 21-hour room temperature fermentation but if you decide to go with the 21-hour room-temperature fermentation, I would be inclined to reduce the amount of yeast and use cooler water. And the higher your room temperature, the more I would cut back on the yeast and the cooler the water I would use. Of course, if you use the 21-hour cold fermentation, you will want to allow for some warmup time, and possibly even proof the dough in a warm/humid environment once it has been fitted in the pan.
I'm sure that buzz and other Chicago-style experts have tried all the possibilities and may have some sound advice to offer you.