hi there!
Yay for the long pm nap!!
So, now you know that after a short am nap your lo needs 2 hr 20 min A. This is great! Lots of moms take weeks to find the right As after a short nap!
Now we need to find the right A after a long am nap...How long is your lo's A first thing in the morning when he takes a long am nap? I guess I would try to repeat the same A after a long am nap and see if that's the right one.
How did today's am nap go after 3 hr A?
You did the right thing by having an earlier bedtime. If your lo seemed happy, then that's perfectly fine! After a 1.5 hr nap, 3.5 hrs A may be ok for him. Some babies like to have their longest A before going to bed.