Hi and big hugs! It can be so hard when they need sleep but are too OT to settle. He is sooooo cute, though, isn't he?!
And great work on getting him to sleep in his own crib! Celebrate every victory along the way!
In terms of what's going on now, well, we'll need to see your routine to give us more information. Once we know how your day goes, we can try to tweak that routine to get him (and you) through this. 30 min naps usually mean that he's OT. He was probably ready for more A time initially when the 45 minute naps started, but since those aren't restorative he got OT and began the 30 minute naps.
As you probably know, BW does not advocate any form of CC or CIO, although it's safest to leave your baby for a few minutes if you feel like you are getting supremely frustrated as long as you return a few minutes later to help him through these rough patches. It sounds like that's what you did, I just wanted to reiterate.
Also, is he swaddled? Does he use a paci or have any other props? What temperament is he?
You could try applying pressure at the jolts to help him through that part of his sleep. When he does wake up, does pat/shh not work well to extend his naps?
Sorry for all the questions, but with a little more info maybe we could work together to come up with a plan for you!