Like Greg mentions, except I have/use inlines from 1/4oz to 6 oz but mostly 1 and 2 oz. I use between a 5 to 6 ft leader, on spoon harnesses I run a 3 to 4 ft leader. Not only does speed affect the depth, what direction your trolling as the many currents out on erie cause depth changes on every style and type lure. If your trolling with, across, against the currents all play into your depth. And line type and dia. They are pretty easy to figure out, once you let one out and touch bottom with your hand on the spool lightly at trolling speed, you know your going to end up about 3 to 5 ft off bottom if you don't let any more line out. Depending on where in erie your going to fish, some basic line outs would be 25, 35, 45, 55, 65, 85( if you can even let one out that far and not drag bottom). The walleye should start letting you know where they want the bait. This spring 18 to 22 out was our most productive. I usually run one at 10 ft behind the board way out side as it will take the biggest fish of the day after we start figuring out what colors, speed etc they want. It doesn't take alotof fish, but they are usually the biggest. Even in 45 f.o.w.