How many ml of kitten milk replacement is typically used up in a feeding? the kittens are 3wks 2days?

I have recently decided to foster them after the mother was hit by a car. they did belong to an elderly lady who lets her cats come and go( my cat NEVER goes out! ) I have been helping since their birth...3 of the litter of 5 died...we are not sure why...these two have been strong and basically healthy the whole time except for a little eye discharge last week for which we used 0.1 mg of amox suspension per day for a few days until they cleared up along with a few applications of neosporin(the male was worse but both are fine now). i was not able to be there every day so i am not 100% on the details. i have been trying to help as much as possible. I have been letting them drink as much as they want but i am not sure if it is enough...they go through about 10ml between the both of them per feeding...sometimes more...i have some chicken and turkey baby food and kitten fancy feast to help with weaning but they don't seem too interested in it yet. any advice would be helpful :)