I recall "The Juiceman" saying that greens should be no more than 1/3 of a glass of juice. He doesn't count Celery as Greens.
I prefer an assortment of veggies with a Granny Smith Apple. I also stir in Cheyenne pepper to taste (depending on the heat rating of the pepper) and maybe a little fresh ground pepper.
All Organic of course. Changing the greens from day to day, and small amount of Beet which goes along way. Taste pretty good.