When I am using Snap weights, I would say my typical leader length (weight to the spinner) is 50 feet. One reason for using Snap Weights is to reduce the surging of the spinner – which is often needed in dingy water conditions. I think that in the situation where the fish doesn’t see the bait real well, they often track the spinner by vibration and a consistent running spinner will allow them to intercept it more easily.
A second reason for using Snap Weights is to reduce spooking. Yes, even a little weight in front of a spinner can spook walleyes. The big advantage to the Snap Weight is that you can use any length leader you want. I can remember one tournament we had in Saginaw where the water was super clear (out by the Charities), the fish were biting real high – and if you didn’t put out a 150 foot leader you got nearly no bites!
As mentioned the weight of the Snap Weight just depends on how deep you want to go. I like to use fairly light Snap Weights with spinners so that I reduce the angle created by the weight from the In-Line board to the spinner. A reduced angle means better hookups.
That said, the disadvantage to a light Snap Weight is that you often need to put out a longer “Dropper” (line from the board to the weight). So it takes longer to set lines and reel in fish. With open water spinners, I fish 1 ouncers up to 20 feet deep, 2 ouncers up to 30, and 3 ouncers deeper than that.
How fast? I troll spinner based on how good the bite is. In a tough situation (dropping water temps, cold front, low fish populations or small areas of fish) I probably troll at .8 mph. In good bites (aggressive fish, stable weather, high suspended fish) 1.5 to 1.8 isn’t uncommon.