Hes on avent 3 medium flow teat, we Had him on 2 and we thought he was getting tired so we moved him over but it took a while for him to get used to this as we found he gulped quite a lot of air down
I think your right about snacking, he'll take 3oz then he refuses (screams and turns his head) to take any more for about 20minutes ... I thought maybe it was wind that stopped him eating because of his reaction
he also could spend a lot of time playing with the teat than eating. It pretty similar when I tried to feed him myself but he was the same where he latch on great first go then hed slip off and suck the nipple. So after a few weeks of that, me and my nipples couldn't take it any longer I moved him over to bottles.
He loves activity time he probably could go longer but as his feeding takes so long He probably only get 40mins with 20 wind down for a sleep
He slept through the night last night as He took 6oz at his dream feed (which took an hour also) and he's taken slightly more today per feed although still an hour each time