Hey Murdok, I have my own little calculation but I always use the same jig heads, made by Litewirehooks, because the weights of his jig heads are consistent. I weigh all my jig heads out in grains. A 1/16th oz Litewirehook weighs 29 grains. A different brand 1/16th oz jig head could weigh 24 grains or 35 grains so knowing the weight of the jig heads you use is good info. Then you have to take into consideration what size line, the bigger the line the more buoyant it is. Speed also controls depth as well as how much line you have out behind the boat. It's hard to give you the "Perfect" answer but trial and error will teach you more than I can tell you. For example, You can tie on a couple of 1/16th oz jigs and start trolling in about 10-15 ft of water and head for the shallower water. When your jig starts bumping bottom, you know how deep you are pulling at and then adjust from there.....Good Luck...It's definitely addicting!!!!