If you are planning on exclusive pumping, then you would need a "hospital grade" pump. My last one, I used Medela Lactina at home and Ameda at work. With my 2-month old now, I use Symphony at home and Medela Freestyle at work.
Symphony is rental and Freestyle is bought. I started with pumping every 2 hours when LO was born and now pumping every 6 hours. But... I am 多奶媽媽, so I still have at least 32 oz a day.
Although they say Symphony and Freestyle has the same motor, I find the Symphony to be a lot stronger and more useful. I had my baby in LA and the LLL there said... it's like the difference between a Lexus and Toyota, although they are from the same factory.
I have tried to increase milk supply with my first baby when there was a drop. You would have to shorten the interval like you said, and I drank 木瓜+ fish soup plus Mother's Milk (Tea)... it does take a week to increase the milk supply.