So I promised to make my tried-and-true iced brownies for yet another school bake sale tomorrow. The recipe calls for 4 oz of unsweetened chocolate and 2c sugar. I have absolutely no time to go to the store tonight, but I checked my supplies and discovered that I have 3 oz of unsweetened (how that happened I have no idea) and a full box of semisweet. If I throw in 1 oz of semisweet, how much should I cut the sugar? A half-cup? I like them not over-sweet, but then again I'm not eating them. Thanks.