Sorry fixed my usual autocorrect rubbish
Ok...I may be mad...I'm just thinking
What if you got him up if he wakes after 6. So then 4 hrs is 10 let him do 10-12 or as long as you can get. Then CN 4hrs or a bit later...Z did a CN 4hrs20 or so after a nap if it wasn't Long enough or he woke early. He may have fought that CN as he wasn't tired enough. But a car CN around 4 hrs later may work. Offer 20-30 mins and BT 2-2.5 hrs or a little later.
Ie
WU 6
Nap 10-12 (or longer if he can do it)
CN 4.15-4.40 or so (maybe go for drive at 4 ish)
BT 6.45-7
I you get a longer night and he wakes after 6.30-7 and it's solid you could push say
WU 6.45 out of cot 7 (or add a little more A to push nap out closer to 11.15-30)
Nap 11-1 (then 5hrs A)
BT 6 (I know EBT hasn't worked...but if you haven't recently I'd give it one more crack, treat EW like a NW.)
I'm just wondering if its worth going back, just to get him over this OT. Then tryto do a push again in a week or so if you think he needs it.
Like I said...I may be mad