Every baby is different. Mine regularly had 7 oz bottles so I don’t see a problem with giving bigger bottles 🤷♀️ Plus you can never really know how must they get from the breast. Babies are way more efficient than a pump.
My twinnies take 5 ounces of EBM but just like they do when breastfeeding about half an hour later they want a very quick desert and opt for another 1 oz top up, beauty of EBM is it can stay out of the fridge for 6 hours so nice and easy for your childminder to responsive feed xx
My BF baby maxes out at 6 oz breastmilk bottles. And that was around 7 months. You could have them give 4 or 5 oz bottles and let them know they can give another oz or two if baby still seems hungry.