Best time to pump?

Andrea

My daughter is 19 weeks and exclusively breastfed. The past few weeks I’ve started pumping about two hours after she goes to bed, but I only get about 3 oz. I want to build up a larger freezer stash to use for mixing purées, milk baths, donating, etc., but she nurses every 2 hours during the day almost like clockwork. When would be the best time to add in another pumping session or two?