We usually book within the six month window and our luck has been pretty inconsistent with CRT. I'd say more often than not we get it eventually, but sometimes we don't. But trying to search for just one day is not likely to be successful. We search every day of our trip and if a rezzie comes up on any day, we snag it and rearrange our plans (and FPs, if within 60 days) to accommodate being in MK that day. The reasons are: (1) it is a small restaurant by disney standards, (2) it takes a long time to meet the princesses and have a three course meal, so the tables are not turned over as quickly as in, say, a buffet or ordinary table service, meaning fewer overall seatings per day; (3) it's in the castle--that is some serious bucket list stuff for a lot of people so draws kids and adults alike; and (4) you have to prepay, so people are pretty committed once they book.