When fishing in the Columbia I usually am trying to fish both lures near the bottom... so I'll usually run a K15 Kwikfish about 30' back on the ball, then stack either a K16 or a magnum wiggle wart about 8-10' above the ball, much farther back (60-80'). I just about never get a tangle with this rig. But for convenience I'll often just run one line on each downrigger, then run another rod or two on jet divers instead of stacking.

Good luck!