I forgot to come back to you! Sorry!
I'd say you were doing ok really - if he's spitting up a lot the only thing I would change is to go to 3 hourly feeds rather than 4 hours but only offer 4oz, smaller feeds more often can help. For his age, 3 hourly feeds fit the routine you need as he won't have the A time to keep the EASy pattern. You do have some 3 hour intervals, and some a bit shorter maybe regulating a bit will help the spitting up (may not though!).
As he is on breastmilk I would expect a smaller feed volume than a formula fed babies, they do seem to need less volume of breastmilk.
Is he burping well? Sometimes needing to burp can look like hunger cues.
Laura