Good advice Montague.

I'd recommend the long string leader to maximize separation between the airframe and the streamer. Alternating pursuer/target roles also will tend to reduce collisions, especially if you stand next to each other and the target tells the pursuer when he's going to maneuver.

I would not recommend using balsa planes in combat. SPADs and other combat planes are built to survive the abuses, or be cheap (emotionally and $$$) to replace.