I agree with Minny on giving the ABA a call. They will be really helpful.

I'd let him feed for as long as he wants on one side. When he starts to fall asleep or his suck changes to light, feathery sucking, take him off, burp him and change his nappy. Then offer the other side for as long as he wants.

You're doing a great job so far and congratulations on the arrival of your little man