I drink, give or take, about four 16 ounce undiluted juices a day, of which, 8 ounces of that 16 ounce glass is comprised of GREENS. The rest is carrot/apple. I also indulge in my favorite pineapple/celery/radish combo whenever I desire. I drink a copious amount of juices. I never limit myself unless my body asks me to.
So, there really isn't a strict set amount to drink. Drink as much as you want. Play around, experiment until you find the amount your body needs. Your body will most definitely let you know. Use fresh ginger and garlic in your juices, as well, to dress them up if you like. But do, please, include those greens.