To answer your questions -
If LO doesn't nap for at least 1hr15 - 1hr30 (i.e. two sleep cycles), he wakes up tired and crying. Even when he does wake up after two sleep cycles he sometimes still is moaning, but usually fine. He's always smiling at me when he wakes up after a 2hr nap, but these are very rare these days. Going by his behaviour. I consider 1 sleep cycle (any nap under an hour) too short and two sleep cycles sufficient, especially if it's 1.5 hrs (rather than 1hr15). I agree that stretching the A in the morning seems to work to get him to nap about 1hr20-1hr30 but like you say it depends on EW and number of NW whether we can stretch it (sometimes he seems exhausted after 1hr45 2hrs already) as well as what we do during that tine. If we go out with the dogs during that activity slot, it stretches it a lot, but sitting in the buggy staring at trees is very relaxing for him (compared to say sitting in his jumperoo, another favourite!). He went down for his naps on Thursday very well (having a warm sleeping bag fresh from the tumble drying certainly helped with the pm nap!!). I always have to help him to sleep, with shush-pat over my shoulder (in cot doesn't work) and often I have to pupd a couple of times before he'll go asleep when I put him down after shush-pat over shoulder. I guess I kinda combine the two methods, as to start with he's still quite wild in m arms or will start crying as soon as I put him down. But mostly he's asleep within 5-10 minutes for naps (if timed right).
I will continue sleep taining during the day and feed during NW, but my new 'rule' is there has to be at least 4 hrs between NW for me to feed him (or roundabout that), with the exception of the first night feed for which he usually wakes up by himself around 10-11pm. Does that sound ok? He does fall asleep on the boob during night feeds. I think it's when I would feed him for all NW including EW that feeding would seem 'useless' as it didn't get him back to sleep. He's not had to many NW after the 4am mark recently though, but the EW before 6am remain. Would be great if that could be stretched until 6.30am or even 7am! I am totally happy feeding him twice a night (if he falls asleep nursing), that indeed is my 'dream night' at the moment and what I'm aiming for. I don't have the (unrealistic) expectation he'll sleep through even more, but 5-6 hour stretches would be great.
He seems to do better when he wakes up for his first MONF around midnight, rather than waking up around DF time of 10-11pm (i.e. after a 5 hr stretch, rather than a 3-4 hr sleep - assuming a 7pm BT). Although he does take a full feed also at 10pm and falls back asleep. I do wonder though how much this is habitual, rather than hunger and wonder whether it's worthwhile trying to not feed him before, say 11pm (do shush-pat/pupd if he wakes before that)?
I did wonder whether he needs the CN or whether that could be a cause for NW / EW? As without APOP it is a nightmare to get him to sleep for that one (and things don't seem any better with that CN).
I think we have overcome the shush-pat aversion, by only doing it over the shoulder and as described above, combining it with pupd when he's kicking and arching his back, or when he starts crying again (or continues crying) when I lay him down. This does seem to work for him and when he's then finally quiet in his cot, I just need to 'manage' the shaking head (looking for nipple perhaps?) and flinging arms. I usually put my hand and/or his lovey against his face, as this stops the head shaking and calms him and sometimes hold his arms, which also helps). So I agree it's probably more a matter of looking at the routine now, as I feel I can calm him again.
Sorry for the long post, appreciate your thoughts!!