Hi there!
Happy for you to jump in!
Will try & answer your Q's best I can ,I'm sure Jackman will chip in too!
I don't let DS sleep for more than 2 hrs, theory behind this is that too much daytime sleep can rob nightime sleep so Tracy recommends naps of no more than 2hrs, tho of course you need to be your own judge on this i.e. if your LO hasn't had much sleep that day & i v. tired you could go over 2hrs.
When I can't settle DS, I get him up and start A time from then (although it will be shorter than normal A time as they will still be tired), so for example DS's usual A time at the mo is 1hr 40mins-ish, it might be an hr or so after a short nap. EASY then can become EASAE if that makes sense??
I would probably adjust A time 5 to 10 mins at a time & see how that goes, I've found even 5 mins can make a difference.
I've not founs ssh pat or PU/PD to work on extending naps.....HTTJ seems to work best for me along with getting A time right...easier said than done though!!