RE: What is the best decoy spread?
For divers, the best setup usually includes some kind of long line. You have one line extending out a ways and comes back to you. You can hook it at the end or not.
What I like to see is a long line of decoys extending straight out on one side. Whatever side you pick for your long line, the other side of your blind should be decoys in a bunch with the area right in front of you wide open. Look at pictures of divers when they feed. They are bunched up tight. Not like puddlers, who only bunch up when they are going to flush.
Theory is that when divers hit that long line, they'll follow it and then swing in front of you to get to the feeding bunch.
I don't know that I'd be mixing teal and 'bills. You've got a small puddler mixed with a medium sized diver. Those two species of birds are rarely found in the same groups. Well, up here in the NE anyway.