Couple more questions - what happens at 5am, do you get him up and start your day?
Also, in your first post you say that 10.5hrs is his usual night (not OT), but in your 'shooting for' routine you've got an 11.5hr night. If 10.5hrs is a normal night for him, and he's not one to tack on, then there's really no option but to keep pushing that nap a little later (hoping for a nice long one) and for a later bedtime, and accept that some OT is goign to be pretty much inevitable until he sort of 'grows into' this routine. Trouble is, with a 10.5hr night as normal and a 13.5hr day, he's going to have to be able to manage long-ish A times AND pull a long nap to get through it. So like 2 x 5.5hr A times and a 2.5hr nap.
Does he EVER tack on over night - or is it a complete no-no? How early have you done bedtime?