Use a dozen blacks and 1/2 dozen mallards throw in some buff's.
Mallard will regulary decoy to blacks (so will alot of other birds)but not always the other way around. Don't worry about call. Learn when and how. Black's are not anywhere near as "talkative" as mallards and a much warier bird. I used to hunt the Meadowlands and Barnegat and up in Maine and after years of experience found building a spread around Blacks over mallards was the way to go.
I do have a question though did they raise the limit on Blacks. Back in the day of points they were a 100 pt bird and even after the point system was done away with you were only allowed one in the daily bag.