If you are going to EP, I would suggest renting a hospital-grade pump. You will get a better output in shorter amounts of time. I get to use one occasionally at work, and there is a big difference.
You may only need to use it for a couple of months until your baby starts solids, then you won't feel the pressure to produce so much all the time, kwim?
So that's at least 5-6 sessions per day, by my calculations?