Hi Kayra
I pumped twice a day, first and second feed of the day, from when O was about 2 weeks old. I wanted to build up a stash for DF and for going back to work at 4 mths. I never seemed to have OS/OAL issues with him and he coped really well with breast to bottle and back again. He did self wean very suddenly and quickly but I think this was due to me not being around all day for little sips at 1 yr plus, as Emma did the same and was never fed by bottle really...
So, worked fine with him.
With Emma, I started with the same plan in mind but she was a very erratic, frantic feeder and what I had pumped I had to use every evening to settle her for bedtime rather than DF as otherwise, she was a little mess! So DF was from the breast, bottle of ebm was 7-7,30 pm after unsuccessful breastfeed. I started to pump at this time, once she was in bed to try and improve things and from around 8-9 weeks, I was able to ditch the pump and the bottle altogether and though I went back to work at 7mths, she never took a bottle.
Also, even without pumping, I was in awful OS/OAL territory with her. I think its easier to get there 2nd time around and when there's some emotional issues - low weight gain or weight loss in Es case as well as a tongue tie they refused to clip - my body went into overdrive very very easily...
With twins, I would be prepared to pump and have that hosp grade pump ready for sure as they are probably going to be smaller, with weaker sucks etc.
My friend had triplets and managed to bottle feed them only EBM for the first 2-3 months (they were so teeny that they were tube fed her colostrum and early milk to begin with) and then she mix fed bm and formula till they were a year old - all from bottles....but she had her mum living with her, her DH at home also fulltime as friend was the main earner and she got great mat leave as they were born in July (hol time so she didn't start mat leave till Sept) and she was off till May fully paid, then came back to work for 5 hrs a day and pumped for probably an hour of that (2 half hour breaks) as here you get one hr off for breastfeeding per child so she worked three hours less till the summer hols! She was amazing but she says she'd never have been able to do it without the support of her mum and DH. Her kids (two girls, identical twins and one boy) are now 8.5yrs old and doing so well!
S x
as for filling and emptying, your breasts are never truly empty but just resting. Emptying or pumping the breasts until no more comes out is the 2nd most effective way of increasing milk supply after a very good, well latched, human feeder. THe feedback mechanism is - breast was completely emptied, more milk needed.