Sorry IShall, can't help from personal experience. However, a mum I met at baby massage is EBMing and has been since birth (baby is 4 months). For her there were medical reasons why she started EBM rather than BF and she could switch to boob now but chose not to as things are going pretty well (sleeping through, grrr).
So it can be done. This lady expresses a lot though, more than she gives to the baby. She is keen to keep up her supply in case of growth spurts.
There have been some issues with my EBF DD's weight over the past 2 months which have finally resulted in a referral to a paediatrician at the hospital. She will feed only 5/6 times a day (believe me I've tried more but she won't have it) has 3 spoon fed meals a day (I wanted to BLW but needed to get the food actually in to her) but will not gain weight. Over the past month she hasn't gained a single ounce. And only just 1lb in the last 3.
She has a bottle of EBM in the afternoon now and I have no trouble expressing enough to get it. So I can actually see what she's getting I'm considering giving EBM for all her feeds.
Has anyone done this? How much do they need? How many times a day do you pump?
She's 6.5months and weighs 13lb 11oz if age/weight makes a difference.