I wasn't seeing any availability trying to book an ADR for 2 people at my 180+8 mark. I decided to try and see if there was availability for 1, and still nothing. Then I thought, what the heck, and tried 3 people and lo and behold there was one. I booked it, then went into it and was able to modify it to make it for only 2 people. I did the same thing for another ADR, but this time it needed me to input FOUR people in order to find it.
So my tip is, mess around with your party size, book, then modify. If I hadn't tried this, I would have missed out on 2 important-to-me ADRs. Hope it helps someone else, too!