Good questiondonnabking. I should have probably been more precise about the recipe, but I don't usually measure it.
But I would say that to 1 cup of milk, you would add about 3-4 drops each of oil and dish washing liquid, and one drop of vinegar. I have added more than 3 drops before though and have not noticed any problems. I never increase the vinegar though. If you play around with the recipe and come up with a better ratio, I would be very interested in knowing.