[Suicide Junkie]

It should also be noted that once the ships pick a target, they will stick with it for quite a while.
If those CA decoys are the only thing in range, then they would be the only choice for targetting.

"Most damaged" is probably a good choice, since the Decoys won't take damage.

You might want to try out the targetting priorities in the simulator.
Add a decoy and a warship to player 1, and set your ships to player 2.
Let the AI run your ships, while you take care to keep both decoy and warship side by side. You want them both to be the same distance from your ships so that they come into firing range at the same time.