By far I am no expert but have done a lot of long line trolling on a number of lakes and there are a few things I am sure of. Depth and speed are highly important. I believe it is better to have your jigs running above the fish than below. The only time I use two jigs is when I am fishing in water deeper than 10 feet and the fish are holding really deep, say 15 feet or so. I usually fish 1/16th or 1/24th. If I need to get deeper I add a small split shot a foot or so above the jig. If you fish two I would advise putting the heaviest of the two on the bottom. I hope this helps you but I am sure there are opinions from people who know more than me. Just adjust size, speed and color and let the fish tell you what the want. If I am fishing shallow water and get the depth and speed keyed in I sometimes use planner boards. You can really adjust your depth and often fish slower if you are in an area where fish are really congregated in a small area.