Black ducks have a well earned reputation for being pretty wary. I'm not sure that this is common knowledge among the ducks, though. Still, if it were me, I'd have a couple of blacks in the rig. I'd also go with a couple of those puddler packs. The key is to match your setup to what the birds in your area are doing. For example, like you, we get mostly mallards. But there is a pretty good percentage of coastal blacks, too. In addition we get a good number of wigeon and gadwall. Occasionally we might see some teal or woodies, but they're pretty rare. Even more rare are pintails. We've tried including woodies, teal and pintails in the rig, but it didn't seem to make any difference. On the other hand, the birds seem more at ease when they see blacks and gadwalls.
I feel slightly sorry for a man who has never patterned his gun, who has no idea how far his chosen load will retain killing penetration. But I'm extremely sorry for the ducks he shoots at beyond the killing range of his gun and load - Bob Brister