When trolling an area with steep drop-offs and a lot of contours I have found that the downrods are the hottest setup going. If you can run more rods then make the additional ones downrods too. If you have them, downriggers are also a good option. Both downrods and downriggers can be run with short lines, like about 10 to 15 feet of line on the downrods and about 6 feet of line back from the cannonballs on the downriggers. Set them short like that and the lures will follow the track of the boat perfectly. When you are trolling that kind of intense structure long lines will cut corners and not stay in the zone and obviously boards will be way out of it. Stick with your downrods - and downriggers if you have them. When trolling around inland lakes, or in areas of Lake St. Clair  or Lake Erie with steep drop-offs, you can also set the lines differently depending on which side of the boat the rods are on. The downrods on the deeper side can be set a little longer and/or with more weight to get the lures down more. You can set the cannon balls at different depths too. The goal is to keep the all the lures as close to the structure as possible. A typical set up might be like this: As you can see from the picture a few feet of deviation in the boat path would cause the lures to get weeded, hit bottom or get out of the fish zone. If you reverse course then you will need to reverse the way the lines are set. I have found that for inland lakes it's easier to troll in a clockwise direction. That way I can keep an eye on the shoreline while fishing, which is a good idea if there are docks and rafts and other hazards to navigation. As you drive around the lake, or down the structure line, and you are doing it right you will be constantly steering the boat and making turns. This will cause the lures on either side of the boat to speed up and slow down. I believe that this erratic action of the lures adds even more fish catching effectiveness. Once you get good at this technique you can keep your lures in the fish zone nearly 100% of the time. You will also find all kinds individual structures that you probably never realized were there. You will be able to see which ones are holding fish, and even identify specific big fish. If you find a big one you can loop around and go over it again, even more than once. I have done this many times and got strikes on the second, third, and even fourth pass over the same fish. I guess that eventually the muskie  walleye  Pike got pissed off with the lures in it's face and it hit. The only drawbacks of this technique are that it is difficult to do alone and it tends to burn you out after a while. That's why you need to have your buds along to watch where you are going and to take over driving when your eyes start bugging out of your head from watching the screen too long.

DOUBLERIG: A set-up where 2 lures are run off one line, almost always on a downrod.

SLIDER: A second line fished from the line going to the outside of the board. It is positioned by a second release attached to the planer board cable 1/2 way out. The slider attaches to the main line and it slides down to the second release where it conveniently stops until a hog muskie slams it