I use the Cromwell and Cruthers stuff... instructions are to wet face, apply 5 drops oil to one hand, rub hands together, then rub hands over face. I have a fairly large head/face 5 drops is usually plenty, maybe 6 for good measure, but that's it.
It's great stuff provided you're shaving every day, not very good for heavy growth.
Also has a downside in the winter, if you're wetting your face, it means you're handling extra water inside the tent, extra chance of spilling somthing or dripping on somthing, though I usually use the stuff anyway, just be careful.