I currently freeze 6oz per bag. This has worked out b/c LO takes 4oz bottles, so I thaw two bags to make three bottles for daycare, which she ALWAYS takes.
Once she turns 1, we want to introduce some WCM but still do mostly BM. I obviously don't want to waste any BM. Is it unreasonable to think she'd drink 12oz of BM plus WCM at daycare? How about 6oz of BM plus WCM?
I have frozen milk dating back to January, so I want to be sure it doesn't expire before she can drink it, but I don't want to run out either. I do plan to nurse her when we are together, so the frozen BM is only for daycare.
I would do the same thing in the cups as you are doing in bottles. You could also combine WCM with some breast milk until she is able to take a serving of the WCM.
I freeze milk in 4 oz and 2 oz bags. I'm just now transitioning her to cows milk, but the plan is to thaw the milk in the refrigerator and pour out of the bag what is needed for the day and save the rest for tomorrow. I think if it's kept in the refrigerator, the thawed milk is probably good for 48 or so hours. I don't have anything to back up the 48 hours. I just smell it to see if it has soured or not. It usually still has chunks of ice in it that time frame.