When fishing Jeff Head, the main rule on down rigger fishing there is never have both rigger's at the same depth. Always try one within 10 feet of the bottom, always, and then another try at 70 first, then 85, then 90, then 60, keep adjusting till ya get fish, but keep one on the bottom cuz you can generally scrape out a fish down there, but often the biters will be in an "unkown" depth, that's why ya keep adjusting the other downrigger. Once the biting depth is established, put all the lines at that depth.
With good electronics you can see the fish at several levels working bait sometimes, generally you will notice one depth consistantly showing fish (not bait, big marks of fish). Use that upper rigger to start fishing that consistent holding depth. There you will have a good chance at finding biters. If bait is popping on the surface, run next to it, not through it. Troll WITH the tide, and adjust speed regularly to find the line angle on your downrigger cable that consistantly produces fish. Depending on current speed, this could be anywhere from 2.54 mph to 6, it is more about the angle on the rigger cable than the speed. The proper angle that tends to catch fish is different from boat to boat, so ya gotta figure that out, But this happens because it is getting the right action on the flasher combo set up you're using. If running straight herring or plug the angle is less important, but with a flasher combo, the flasher imparts a good deal of the action to the lure, it is not just to attract fish. The wrong line angle will have the wrong action and be less likely to consistently produce fish. One last thing, you probably already know this, but here it is anyways. When finding bottom, don't worry about the depth on the rigger compared to reading on depth finder. Just put the ball all the way on the bottom, the come up 5 to 10 feet, after about a minute of trolling, check to find bottom again, then adjust up again. Troll a straight depth line, like 130 or 110 or something, then on the next pass try another depth line.
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Have pole, will fish.