We are battling major EWs but having good naps, so the 12 hour day isn't happening here. I try to keep it within 13 hours, but on a major EW day with good naps I have pushed it longer. My LO never makes up the time at night, but he won't go down earlier after a good nap often.
I'd say if he sleeps until 3, you push until 7:00 but 7:30 might be getting too much later than he is used to. My LO is like yours and we have to keep the last A short.