Right, I'm back 
I've got 4 months old twins who are bfed - well, mostly. DTS has turned into a bottle refuser so he's ebf, DTD will take a bottle so has two bottles of formula a day.
I bfed my 2 previous children with no huge problems - with Ds1 it took a bit of getting used to, sore nips etc, but generally it was ok, and DS2 was pretty good, and a bottle refuser to boot.
I was completely overwhelmed by the thought of bfing twins and set myself abosultely no targets in regard to feeding. I knew I'd give it a go, but that was it - no pressure.
The twins were born by emcs after DTD got into trouble, and they ended up into scbu despite not arriving early or being particularly small. I was also recovering from a general anaesthetic, and didn't even see DTD until late the next day after they were born, so it wasn't the ideal start to bfing. They were drip fed for the first 24 hrs then DTD had a tube up her nose, while DTS started on a bottle of formula. I was still woozy with drugs at this point but began expressing. I couldn't express enough for both of them but they had what I could get and both had formula top ups to begin with .
By about day 3 we were all feeling much better and I tried to bfeed them both. DTD took to it straight away , DTS took a bit of practice but by day 4 we dropped the top ups and we were discharged.
I exclusively bfed them for about 6 weeks I think. I had an EZ2 nurse cushion and it was quite good for tandem feeding, but I still felt they weren't positioned brilliantly, and I used to spend ages faffing around with cushions to get them to the right height and myself comfortable. I also felt completely pinned to the sofa tandem feeding, wheras feeding them one at a time I at least had a hand free, which helped with my other two kids - 4 and 2 at the time.
So I stopped tandem feeding as soon as I could get away with it. I'm lucky that my babies all seem to feed quite quickly, so I used to stall DTD with a dummy (DTS wouldn't take one) while I fed DTS, then fed her.
I was never organised enough to get them on a clockwork routine, so they were often not hungry at the same times anyway, and DTS, my bigger twin, seemed much hungrier and fed more frequently anyway.
I was pleasantly surprised that I never got sore nips though, as I did with both my singletons beforehand. Not sure why really, but bfing is SO much easier when you've done it before, so maybe it was just that.
I've no idea how long I'll carry on for. I'm just taking each day as it comes, and at the moment it's the best option for all of us.
I have never eaten so much in my life though - the hunger and thirst is something else!
My advice would be to take each day as it comes, set yourself no targets unless it's super important to you, and get the hang of feeding them singly before trying tandem, 'cos it's not easy to begin with! I'm on another twin forum and several of the people who didn't manage to bfeed for long, were adamant they had to feed tandem, then found it too hard and gave up. I think they'd have stood a better chance if they'd got the hang of feeding them singly first.