Supplementing with formula

My baby is 11 weeks old and EBF. We have been trying to bottle feed since four weeks and my daughter hates it. A while back, we realized that my expressed breast milk had high lipase content and tasted and smelled like soap. I tried scalding it but the soapy flavor is still there. Today, I decided to try giving her a bottle of formula and she loved it.

I’m going to continue to breastfeed but she’s starting daycare soon and I’m going to let them feed her formula. Since she will be breast fed on demand, how much formula should she eat per session?