try reading " the trollers handbook" by Ray Rychnovsky or try "successful downrigger fishing" By Fred Oleson older but still good. for more up to date info try "Trolling top to bottom" by mark Romanack mostly chapter eight. If you want i am willing to lead them out to you for a day on the water and maybe share what I know.
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Thomas J Elliott
Veterans Realty Services.
1-425-220-6567