Hi CVQ,
Do you know how much he weighs (in kgs)?
Are you any good at maths?
If so there is a crude "rule of thumb" you could try....although with some bf it is going to be ultra-crude.
IIRC A baby should be taking at least 150ml fluid per kg in weight over a 24hr period.
I would assume he is taking approx 7oz at a bf - if that is the volume which satisfies him from a bottle. This is obviously very crude estimate - and bear in mind your overnigh feeds may be more of a comforter/"dummy" so he may actually take minimal milk
So lets assume he weighs 6kg? (off the top of my head - which would be about 12lb).
He needs 6 * 150ml = 900ml.
If he is taking 7oz bottles/feeds = 200ml per feed
So he needs 4 and a half feeds in 24hrs.
So judging by your first post he is gettting this as he seems to be having at least 4 "proper" feeds.
Does that make sense?
I was cautious about posting this - it is not set in stone. And it is crudely calculated - especially with the bf....but it is a start. Don't worry if he only manages 850ml - it is close enough. You only ned to worry if he is consistently below about 600ml I would say.
Also you need to insert his own weight.
My DD3 is 26m - so it seems like an eternity since she was 7m - and I can't remember what she did in practice.