Exclusive pumping?

Anyone exclusively pumping? If so, how much did you have stored before switching to bottle feeding completely? And how many times a day do you pump? I am breastfeeding whenever I'm not working and obviously we are bottle feeding for the days when I work and I feel like not only does my baby act better after bottle feeding but I feel better knowing exactly how much he's getting and when I should be feeding him next. I would like to bottle feed more than breast feed but I'm not sure how much milk I should have stored up ? I only have 40oz right now and I work 20-30 hours a week. My baby takes 4oz every 3 hours.