If it were me, I'd try to go with the bare minimum, especially if you're hoping to keep BF for a while longer.
LOs often find it easier to get milk from a bottle and don't get the "full" signal so readily, so can look like they're still hungry or guzzling feeds when in actuality they've had sufficient but don't realise it yet.
Does she seem satisfied after 4oz if you offer that? Could you give her a few minutes to see how she goes? You can always make up a bit more if she really is hungry then.