I think he might be up too long during the day, 1-2 hours may still be too much for him.

Don't worry about co-sleeping, its a myth that you cant get them out of your bed later - AND you both seem to be getting far more sleep that way...

Hey, he is still really tiny - babies don't come with habits that need to be 'broken', rocking, patting - these are all things that reassure him and help him drift off. 20 mins of rocking/patting isn't too bad though. Its hard when your arms are tired, I know -but it cold be HEAPS worse...believe me! DS didn't sleep more than 8 hrs in 24 and screamed the entire time *sob*.

Hang in there!