They should have as much as they want as often as they want. At 7 weeks, I would say that was probably around 60-90ml every 3-4 hours, maybe 8 feeds a day, but that was partly breast milk and partly formula. She wasn't a very big eater. But really as much as they want and whenever they seem hungry. If your LO is draining every single bottle, I'd offer more until you get to a point where he/she is leaving a little and being satiated after a feed.
My 5 week old has been drinking 4-5oz since he was about 3 weeks old and goes anywhere between 2-4 hours between feeds having 7or8 bottles a day. Every baby is different and needs different amounts, I thought 5oz sounded like a lot at 3 weeks but he obviously needed that amount.
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