How Many ml of Dermal Filler is Normally Used for the Face?

Without photographs, ample discussion, and an examination I am unable to give you specific advice, but will try to help with some general thoughts about soft tissue fillers.  

You need to carefully evaluate your goals and expectations before deciding on where and how much filler to use.  It sounds from your description that the two physicians that you saw are recommending completely different types of treatments.  You should be sure to explain to them which areas you are concerned with.  If you are trying to achieve any significant augmentation to the malar (upper cheek) area, one cc will not be enough.  If you plan to treat the nasolabial folds, the malar region, and the tear troughs you will need at least 2-3 cc's.  It is not inconceivable that you might require 4 cc's.  Consider meeting again with one or both of the physicians to more fully discuss your goals.  Good luck.

The amount of filler used is variable, It really depends upon how you look and what you want to achieve.  I have used as little as a 1/2 syringe for some people and up to 5 in others during any single visit.

The amount of filler required to achieve a patient's desired aesthetics result varies greatly. With filler you will be able to evaluate the result immediately and decide for yourself if you would like a greater amount of correction/ increase in volume. 4 mL is a reasonable amount filler for someone to need. Some areas, like the temples, can require up to 8 syringes of filler.