Expressed breast milk feedings

I had been successfully breastfeeding with the aid of a nipple shield for 3 months. However, after attempting to wean off the shield, my LO now refuses to nurse most of the time with or without the shield and only nurses at night and if he is in the mood during the day I guess! It's frustrating and I think I'm going to transition to EP for daytime feedings.  I've read 1 oz per hour but feel like he guzzles down 3 oz in no time every 2 hours so it's 1 oz over the recommended and still seems hungry.  Paced feedings did not work for me and just makes him more frustrated. How much do you all give per feeding? I don't want to over feed him but want to make sure he's getting what he needs.