My child is going to be 29 months at the end of the week and we struggled with this issue in January. It was partly a molar coming through and definitely the nap causing issues. He is close to dropping his nap. He will sleep 12 ONS if he skips his nap. Here is what we do:
1. BTC nap- put down at 1, asleep by 1:15/1:30, cap the nap to ONE hour only
2. PD for bed at 7:45, he is asleep between 8:30/9:00, but usually 8:30.
3. He wakes up mostly at 7:00, but I start his day no later than 7:15
He's getting only about 11-11.5 TS, but if i give him a longer nap like 1.5 hours he only sleeps 9.5 hours at night or less! He doesn't settle for bed till 9:30/10:00. We were getting 12 TS till January and that's when his sleep pattern changed. He can skip a nap for a day but then needs it the next day, so we aren't going to completely drop it yet. I might alternate when the time gets closer.