Q. Is it best to pump right after feeding, midway between feedings - or does it not matter? I am trying to build up a reserve of expressed milk. Also, is there a time of day that is best?
A. Between feedings is best~not too soon after one and not too close to the next.
The best time of day is probably when you yourself feel most relaxed. For some women, that is early morning, for others, later in the evening. Four to 5 ounces is fine, since you are expressing "just in case".