I have not read the other threads.
But here is my tuppence worth.
My DS refused to feed, he was very determined (signs of things to come). My self and DH harvested for the want of a better word the colostrum with a syringe type set up and drip fed it to him .
I then started to express and I am so glad I did, FWIW I had enough milk to flood a small village
He was born on the Saturday, I felt progressively unwell over the next few days, I ended up in Intensive care in heart failure on the Wednesday. Between the jigs and the reels, by the following Saturday I had been diagnosed with post partum cardiomyopathy, and I was placed on life saving drugs, which meant I could not breastfeed or express any longer.
Just read this back and it is a very long answer, but in essence what I am trying to say is that in expressing more or less from day one, I had loads of milk.
HTH