"My sources" (Corinne Netzer's book and
www.calorieking.com) give general info for the average dry wine. Corinne says 25 cal/oz, which would be an even 4 points for 8 oz. Calorie King says 88 cal for 4 oz (22 cal/oz), which puts 8 oz
just over the line to 4 points. These are averages and there may be some wines which are less. I think you're safer to go on counting it as 1 point/2 oz, because between the imprecision of your measurements (which probably increases the more you drink) and the uncertainty of the information, it's good to have some room for error.