I just weighed 3 oz. of sugar (didn't have any regular jello) in a measuring cup. It weighed almost exactly 1/2 way between the 1/3 mark and the 1/2 mark. I have a box of sugar free jello and it weighs .3 oz. The sugar free jello measures 1 Tbsp. So, I would go with a heaping 1/3 cup of jello to 2 cups of water.
bkay