Hi silversands I am mother of twin daughters, both of whom now have twins. The youngest twin girls were born at 30 weeks, weighing 2lbs and 2 lbs 10 ozs. They stayed in hospital till they reached 4lbs, by which time they had transferred to formula milk and were taking about 80 mls every 3 hours. Because they had been in the SCBU, the nurses had them on a structured feeding regime and they were fed at midnight, 3 am, then 6 am, which continued till they weighed about 7lbs and could go for longer. My daughter dropped the 3 am feed and they woke once in the night, between 4 and 5 am, by the time they were the corrected age of 2 months old (4.1/2 months after birth). Then, she started to give them their last feed at about 10 pm, and they would wake up once (she fed whoever woke first and then woke the other for a feed). Within a couple of weeks, they went through the night - it all happened gradually, aided by a dummy hastily stuffed back in if she thought they didn't need feeding for another hour.
It's hard work with twins because they disturb each other and you take longer o complete night feeds - my two were feeding every other hour or so, not together, which was tiring. If the babies are over 8 lbs, they could go from midnight to 6 am without too much trouble. It's knackering with one baby, let alone twins.
TAMBA (Twins And Multiple Brths Assocation) is helpful and you can network wth ther twin families for support and socialising. They welcome grandparents, too.