I iced them on Tuesday for Thursday. I think giving myself the extra day was a good idea. They wouldn't have dried enough overnight, not enough to risk stacking them or putting plastic wrap on top of them in the morning for transport. Also, making them a thick cookie really helped with not getting stale. At Christmas my thin cookies were stale pretty fast because you need to leave them out and uncovered until they dry- overnight or a day.
My cookies today were soft and chewy, with a hard crust of icing. Yeah! They look sort of matte, not shiny like last night which is too bad, but they are intact! This wasn't the case at Thanksgiving. I put the cookies on a tray the day after I iced them and put plastic wrap over it. Duh. Too soon. The icing stuck to the plastic wrap and came off in clumps.
Make a mistake, learn from it!