Book it now, if you can. We just decided to make a trip in mid May (first trip with DS2, though we've been ourselves many times), and I've been shocked by the difficulty of getting ADRs compared with previous trips. Granted, we started planning relatively late and didn't get the chance to book months ahead, but I even remarked to the person at CRO that I remember making a same-day reservation at Chef Mickey's on the Fourth of July several years ago. Her response was that with the popularity of the dining plans many more people book TS meals, and especially character meals. The per head cost just isn't much of an issue/crowd controller anymore.
For the five nights that we'll be on property, there was ONE dinner slot available, that's any day, any time. I grabbed it.