How much does your 5 month old eat?

My daughter is EBF and has never taken a bottle. She eats every 1.25 hours. We have a date night Friday and my mom will be watching her. We got her to take a sippy, so she won’t starve. But how much milk should I expect her to need? I did a weighted feed 2 months ago and she ate about 3.5 ounces. We will be gone for about 6 hours, but she should only be awake for 2.5-3 of those.