Whent to start supplements (c section)

This is my third child. I have a history of low supply. We made it nursing 14 weeks with my first, 8 months with my 2nd(NICU preemie) both needed formula from day 1. I have PCOS and we believe reduced milk glands. I'm having a c section Friday I'm trying to prepare as best as I can. I have Fenugreek and Sunflower lechitin on hand already. Should I start them before she is born?

Also I am wanting to do one of the supplements to replace doing the mother's milk tea, what do you guys recommend?

Sorry for the long post, I wanted to get all the details in that I could.