Optimum amount of wine daily

[JDA]

For someone who is allowed wine daily but has to limit alcoholic intake for health reasons, how many ounces of wine (daily) do you think would be acceptable?
Wine glasses vary so much in size, what is the right amount of Chardonnay to pour in one glass? (With hard liquor it is 1 1/2 ounces to the glass.)
I would appreciate your input.