I would say call for the ADR at the 180 day mark. Judging from these boards it fills up very fast. We are going to the dinner at CRT and called for it 180 days out and had no problem. Good Luck hope you have a great trip!
I would call at the 180 mark just to be sure but....
I just had Disney Dining on the phone to ask about LTT on the MNSSHP night and just for the heck of it asked if they had any openings for CRT breakfast, lunch or dinner for the day of DD's birthday on September28 for 4. She had a bunch of time slots open for all 3 meals.
Last year, we visited WDW during the same time period. Myself and my mom called at exactly 90 days out (earliest at that time) for CRT breakfast. We both got through, but got one of the last times available. All times were gone by 7:05am, because after I gave her all my info and looked at the time it was 7:03am.