Hi there! I'm sorry you're still having a rough go with sleep. You'll have to remind me of a few things; have you tried PU/PD with your LO? Also, what is your baby's temperament? (spirited, angel, textbook, grumpy). I often find with my LO, I can put him down a little early if he's tired, but so help me if I put him down late. Do you find there is a magic time that makes a difference? In the morning you had him up for 2hr 26mins but in the afternoon he was awake for 2hrs and 35 mins, then 2hrs and 34mins before bed time. Is the magic number perhaps 2.5hr?
I also wonder, if he naps really well in the morning, perhaps you should really work that nap. Let him sleep for 2-2.5hrs if he will, anticipating that the afternoon will be a short nap? I'm just throwing ideas around because I know you've been dealing with this for some time.