Agreed, supply is often thrown around but very very rarely the issue.
I combination fed purely for some sleep as my LO was very very slow feeder, she would be an hour and a half each feed with maybe an hour or two in between, by day 8/9 I was a danger to myself and to her, I actually walked into the toilet door, fell over my own feet in the hall and was a complete mess! My DH taking a feed gave me the rest I needed to be a better mum.
If you choose to go down that road it may be trial and error,
Dr browns bottles caused chaos with her latch and took my 3 days to fix it but the tommee tippee where fine.
Remember midwives have to officially follow the guidance, if you get a good one they often say - I'm not supposed to say this but from experience.....
My MIL is a infant feeding lead and said 1 comp feed (bottle) a day won't do any harm. It also meant when she was a little older I could escape to the hairdressers for a couple of hours and she could be fed (either expressed or formula)
If you are going combi then the worst time to do it is at night when your prolactin is highest ( have a little read at kelly mum or jack Newman on this).
There is SO much advice and guidelines out there that it makes us lose trust in our own instincts- you know in your heart what is right for you and your baby. As long as there are plenty of wet and dirty nappies, you are both doing just fine xxx